Handbook of Language and Literacy Development - a Roadmap from 0 to 60 Months

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Introduction to Language 25 - 36 Months - Understanding and Using More Words and Structuresclick to print Print
Research Review / Parent

Written by: Carrie Gotzke and Heather Sample Gosse, University of Alberta

In the 25 to 36 month period, toddlers make many gains in both their understanding and use of language. The size of their receptive and expressive vocabularies continues to increase. Toddlers begin to use grammatical morphemes, pronouns and auxiliary verbs. These developments allow them to produce longer and more complex utterances, including more adult-like forms of negatives, imperatives and questions. Their phonological systems are further refined as they produce words with different syllable structures. Language continues to develop in the context of interaction with others. For information on this critical context, please refer to Interacting.

Understanding and Using New Words - Ever-Increasing Vocabularies

Twenty-four to thirty-six month-old toddlers' receptive vocabularies continue to grow alongside their expressive vocabularies. Toddlers comprehend words one word at a time, first understanding general words (e.g., do) and then more specific words (e.g., eat) (Pan, 2005). Their expressive vocabularies continue to expand as they learn more nouns, verbs, adjectives, and adverbs. They also begin to produce more closed-class words such as prepositions, pronouns, conjunctions, and auxiliary verbs. Toddlers may still produce babbling, jargon and protowords, but with less frequency.

Vocabulary Growth

By 24 months, toddlers had developed expressive vocabularies of over 100 words. In the 25 to 36 month period, their expressive vocabularies rapidly increase (Hulit & Howard, 2002). By about 30 months, they may have expressive vocabularies of 400 words. By 36 months, their expressive vocabularies may have increased to over 1000 words (Apel & Masterson, 2001). Caregivers' expansions of toddlers' utterances may support their vocabulary growth.

Closed-class Words

When they first started to talk, toddlers used few closed-class words in their utterances. In the 25 to 36 month period, they begin to use prepositions (to describe locations), articles, auxiliary verbs, conjunctions, and pronouns. Closed-class words make toddlers' utterances more grammatical.

Prepositions

In the 13 to 24 month period, toddlers may have begun to use the prepositions in and on in their utterances (Owens, 2001; Weitzman, 1992). Between 27 and 30 months of age, most toddlers will correctly use these prepositions 90% of the time (Hulit & Howard, 2001; Owens, 2001). Toddlers follow the strategy of using on when they want to describe an object in relation to a surface and in when describing an object in relation to a container. They may not understand that they can use on when describing an object in relation to a container until 36 months of age. In and on are two of the morphemes originally studied by Brown (1973). For more information on Brown’s research, see Brown’s Fourteen Morphemes.

Other early prepositions include away, out, over, and under (Owens, 2001). Prepositions that describe topographical relations (e.g., on, in, under) appear to be easier for toddlers to understand than those that describe dimensional relations (e.g., behind, beside, between, in front of). To understand dimensional prepositions, toddlers must consider the relation of one object to the spatial orientation of another object (Hulit & Howard, 2001). For example, to understand in front of, the toddler must be able to identify the front and the back of the object. When objects do not have readily identifiable fronts and backs (e.g., a ball), this task becomes more difficult. For adults, the front of these kinds of objects is the surface nearest to the listener, while the back is the opposite surface. Toddlers at 30 months also begin to use to as a preposition to indicate direction toward (e.g., Bobby go to school) (Owens, 2001).

To correctly use a preposition, toddlers must first understand its’ meaning. Toddlers use two strategies when trying to understand unfamiliar prepositions (Owens, 2001). These strategies are as follows: “Rule 1: If B is a container, A belongs inside it. Rule 2: If B is supporting surface, A belongs on it” (Owens, 2001, p. 298). Following these rules, it may appear that toddlers always understand in, and understand on only with respect to surfaces and never understand under. Toddlers following these strategies will use the objects mentioned, as opposed to the preposition itself to interpret utterances. Word order and context are also used to understand prepositions.

Conjunctions

Between 25 and 27 months, toddlers begin to use the conjunction and to list two things and to produce compound objects, as in the example, “I want juice and cookie (Owens, 2001; Weitzman, 1992). Prior to this time, they produced naming sequences without a conjunction such as “Coat hat” (Owens, 2001). Around 30 months, toddlers begin to use “and” to join two sentences as per the following example: “I walked and saw puppy” (Tager-Flusberg, 2005). Toddlers may also produce a series of sentences each starting with and (Owens, 2001). For example, toddlers may say, “And I runned. And I falled.” In this situation, and is interpreted as “and then.”

Thirty-month-old toddlers also begin to use because and so (Hulit & Howard, 2001).Appropriate use of these conjunctions is interpreted as evidence that thirty-month-old toddlers understand causality. However, these toddlers are not able to provide complete explanations of how cause and effect are related in a given circumstance.

Pronouns

Pronouns are words used in place of nouns and convey information about gender (or lack thereof) and number of referents (Hulit & Howard, 2001). Pronouns may be subjective (i.e., I, you, he, she, it, we, they) or objective (i.e., me, you, him, her, it, us, them), depending on the position that they are used in a sentence. Generally, toddlers acquire subjective pronouns before objective ones. By 36 months, toddlers master most of these pronouns.

During the 13 to 24 month period, toddlers may have used the pronouns I and it (Hulit & Howard, 2001; Owens, 2001). It generally first appears in unanalyzed wholes (e.g., “Stopit”). They may have also used the demonstrative pronouns this and that (Hulit & Howard, 2001). Between 27 and 30 months, toddlers begin to use my, mine, me and you (Hulit & Howard, 2001; Owens, 2001). You tends to be produced before me, mine and my and is first produced in imperatives, for example, “You go home” (Owens, 2001). Between 31 and 34 months, toddlers begin to produce your, she, he, yours, and we. Toddlers exhibit individual diversity in terms of the order in which pronouns emerge.

Initial use of pronouns is sporadic as toddlers may not use them in all utterances (Owens, 2001). Toddlers may also initially use pronouns incorrectly (Hulit & Howard, 2001; Weitzman, 1992). For example, toddlers may say “Me want cookie” instead of “I want cookie” and “Mine ball” instead of “My ball.” Pronoun confusion is more common in utterances with a noun + verb + noun structure and when imitated (Hulit & Howard, 2001). Toddlers generally do not make errors between types of pronouns (e.g., using I for you) (Owens, 2001). Toddlers’ initial strategy for learning to use pronouns is to use I at the beginning of utterances and me at any other position in the utterance. Gradually, this strategy evolves into the semantic case distinction of subjective and objective.

Auxiliary Verbs

Auxiliary verbs are the only verbs that can be attached to negation (e.g., “I can’t go”) or be inverted with the subject to form questions (e.g., “Can I go play?”) (Owens, 2001). Auxiliaries are also used to avoid repetition in responses and for emphasis. For example, toddlers may avoid repetition by responding “I am” to the question “Who is hungry?”

The age at which toddlers begin to use auxiliary verbs is variable (Hulit & Howard, 2001). At 27 months of age, about 50% of toddlers begin to use the verbs have and do as auxiliary verbs (Hulit & Howard, 2001; Owens, 2001). Around 30 months, can, will, and be begin to be used as auxiliaries (Hulit & Howard, 2001; Owens, 2001; Weitzman, 1992). Thirty-month-old toddlers also begin producing the negative forms of these auxiliaries (i.e., can’t, won’t, don’t) (Owens, 2001). Over time, toddlers become more consistent when using auxiliary verbs (Hulit & Howard, 2001). For more information on the verb “to be” as an auxiliary verb, see the sections on the Uncontractible Auxiliary and Contractible Auxiliary.

Producing New Words - Sounds and Syllable Structures

As their vocabularies grow, toddlers are challenged to produce new sounds and words with different syllable structures. They may simplify the phonological (i.e., sound) and/or syllable structures of new words in order to make them easier to produce. Toddlers engage in word play to learn about sounds and syllable structures.

Sounds

Twenty-four to thirty-six-month-old toddlers may now be using all 24 consonants (stops: /p, b, t, d, k, g/; fricatives: /f, v, s, z, h/, sh, th (as in “the” and “this”), zh; affricates: j and ch; liquids: /l ,r/; glides: /w, j/; nasals: /m, n/, ng (Apel & Masterson, 2001). As some sounds (e.g., /t, d, p, b, m, n, w/) are easier to produce than others (e.g., /k, g, s, z, j, r, l/, sh, ch), toddlers may continue to make errors on sounds within words. At the beginning of this period, toddlers primarily delete difficult sounds, but by 36 months, the majority of errors are substitutions. Toddlers may also make errors on vowels, neutralizing or reducing them to /1/ and /4/ (e.g., “head” as “hud”) (Owens, 2001).

A number of different types of substitutions have been identified in toddlers’ speech (Owens, 2001). Stopping is a substitution pattern in which a fricative or affricate is substituted with a stop (e.g., “do” for “shoe”). Stopping occurs most commonly on initial sounds in words. Toddlers may also “stop” nasal sounds (e.g., “sab” for “Sam”). Fronting is a substitution process in which velars (e.g., /k, g/, ng) and the palatal sh are replaced with alveolars (e.g., /t, d, n, s/). For example, toddlers may produce “cat” as “tat” and “show” as “sew.” Fronting has been identified in 23% of the sounds made by 36-month-old toddlers. Gliding is a substitution process in which liquids are replaced with glides (e.g., “wock” for “rock”). Gliding may persist into the school years. Finally, toddlers may substitute vowels for syllabic nasals or liquids (e.g., “fawa” for “flower”).

Assimilation is another process that has been identified in toddlers’ word productions. In assimilation, toddlers simplify production by producing different sounds in the same way (Owens, 2001). When assimilation occurs on neighbouring sounds, it is called contiguous assimilation. When it occurs on sounds that are apart, it is called discontiguous assimilation. Progressive assimilation occurs when a sound influences the sound following it (e.g., “doddie” for “doggie”); regressive assimilation occurs when a sound influences the sound before it (e.g., “goggie” for “doggie”). Regressive contiguous assimilation may occur when the voicing of a vowel affects the preceding consonant (e.g., “dop” for “top”). Backing is the most common type of noncontiguous assimilation. Backing occurs when “one consonant is modified toward another that is produced farther back in the oral cavity” (e.g., “cake” for “take”) (Owens, 2001, p 344).

Syllable Structures

In the 25-36 month period, toddlers expand the number of different syllable shapes they produce. They continue to simplify syllable structures to make words easier to produce.

Syllable Shapes

By 24 months, toddlers produce words with the following syllable shapes: vowel-consonant (e.g., up), consonant-vowel (e.g., bye), consonant-vowel-consonant (e.g., sad), and consonant-vowel-consonant-vowel (e.g., puppy) (Owens, 2001). By 36 months, toddlers will produce words containing the following syllable structures: consonant-vowel, vowel-consonant, consonant-vowel-consonant, consonant-consonant-vowel (e.g., sky), consonant-consonant-vowel-consonant (e.g., stop), consonant-vowel-consonant-consonant (e.g., tops) and vowel-consonant-consonant (e.g., eggs). Throughout this period, words are generally not longer than two syllables.

Simplifying Syllable Structures

As in the previous year, twenty-four- to thirty-six-month-old toddlers continue to reduce words to either consonant-vowel or CVCV forms, thereby simplifying their production. Most frequently, these processes affect the final consonants. Toddlers may also simplify multi-syllabic words and consonant clusters within words.

Simplifying CVC words.

Toddlers may either delete the final consonant (e.g., producing “hat” as “ha”) or add a vowel sound following the final consonant (e.g., producing “hat” as “hat-a”). Vowel insertion is also known as epenthesis. To facilitate production, toddlers may also lengthen the vowel preceding the final consonant (e.g., caaat) or substitute a glottal stop or /h/ for the final consonant (e.g., “cah”) Insert audio. Epenthesis after a final consonant, vowel lengthening and substitution of glottals are also steps in acquiring final consonants. Generally, toddlers will produce correctly CVC words with a nasal sound in final position first (e.g., “can”). By 36 months, final consonant processes are no longer evident in toddlers’ speech.

Simplifying multisyllabic words.

Toddlers may also reduplicate syllables within words as a way of simplifying syllable structure (Owens, 2001). In reduplication, one syllable becomes more similar to another (e.g., “water” produced as “wawa”). Syllable stress and order appears to affect which syllable within a word is reduplicated. Usually, the final syllable is reduplicated. Toddlers may reduplicate the final syllable because, when preceded by an unstressed syllable, it has an increased duration and increased emphasis. For example, in elephant, the final syllable is preceded by an unstressed syllable. Toddlers may produce “elephant” as “ehfafa,” reduplicating the final syllable. In other cases, the most clearly stressed syllable is reduplicated. Reduplication is also a step in the acquisition of final consonants and is usually no longer heard after 30 months.

To simplify production, toddlers may also delete unstressed syllables, for example, producing “away” as “way” (Owens, 2001). Initially, toddlers delete unstressed syllables in any position in the word but gradually only delete these syllables when found in the initial position. Unstressed syllable deletion may continue until 48 months.

Simplifying consonant clusters.

Toddlers also simplify words by reducing or simplifying consonant clusters (Owens, 2001). Most frequently, toddlers will delete a consonant from the cluster during their production. Which consonant is deleted is affected by both the language being learned and the toddlers themselves. For toddlers learning English, some predictable patterns include deletion of /s/ in /s/ + stop clusters (e.g., “pill” for “spill”), deletion of the liquid (/l, r/) or glide (/w/) in stop/fricative + liquid/glide clusters (e.g., ““teet” for “tweet”, “fog” for “frog” ), and deletion of the nasal in fricative + nasal clusters (e.g., “bup” for “bump”). Other toddlers may insert a vowel in the middle of the cluster (e.g., “buloo” for “blue”). Cluster reduction may continue until 48 months. However, toddlers are generally able to produce some consonant clusters at either the end or beginning of words by 36 months.

Learning about Sounds and Syllable Structures

Word play is one way in which toddlers learn about sounds and syllable structures. Twenty-four to thirty-six-month-old toddlers may engage in rhyming as word play (Pan, 2005). Rhyming involves "implicit comparison and matching of phonological sequences" (Pan, 2005, p. 133). In another form of word play, toddlers may recognize that some words have other words within them (e.g., hammer includes ham).

Producing Longer Utterances

Through expansions and recombinations of two-word utterances, toddlers increase the length of their utterances in the 25 to 36 month period. Around 30 months, toddlers become aware that utterances must contain both a noun and verb phrase, which also leads to the production of longer utterances (Hulit & Howard, 2001). This awareness allows toddlers to begin using word order as a cue to understanding longer utterances. However, word order is not used as a primary tool for comprehension until after 36 months. With their growing vocabulary, toddlers expand noun and verb phrases. As well, they begin to use smaller units of meaning known as morphemes which also leads to an increase in the length and complexity of their utterances.

Combining and Expanding

Once toddlers are producing equal numbers of one and two-word utterances, they begin to produce three-word utterances (Owens, 2001; Weitzman, 1992). These utterances may be one of two types: 1) recombinations of two-word utterances (e.g., “Baby eat” + “Eat cookie” becomes “Baby eat cookie”) and 2) expansions of existing sentences to express attribution, possession or recurrence (e.g., Eat big cookie). The most common three-word utterances are agent + action + object (e.g., Baby color crayons) and agent + action + location (e.g., Doggie sleep yard) (Owens, 2001). Toddlers may also combine language functions within a single utterance (Owens, 2001). In the example, “Mommy cookies hot?” the toddler is requesting both information and an object. Utterances are expanded to four words in the same way as three-word utterances. Toddlers may be producing some four word utterances at 24 months of age. As toddlers’ utterances increase in length, caregivers expand their toddlers’ utterances less frequently (Owens, 2001).

Toddlers continue to use language to request objects, request action, obtain information, and to respond to questions or comments (Hulit & Howard, 2001). Reflexive expansions, which began to appear late in the second year, continue to function for recurrence (e.g., More milk) and nonexistence (e.g., No bed). In the previous year, reflexive expansions accounted for 70% of utterances (Owens, 2001). This percentage decreases to less than 10% by 36 months. By 30 months, toddlers master attributive utterances that describe physical characteristics (e.g., Big doggie).

Modifying Noun Phrases

Between 27 and 30 months, toddlers become able to modify nouns in the object position in utterances (e.g., Daddy is big man) and nouns that stand alone (e.g., Pretty mommy) (Hulit & Howard, 2001). They tend to modify noun phrases using adjectives and articles (i.e., a, the). Over the next three months, toddlers become able to elaborate nouns in the subject position in utterances (e.g., Big boy is mean) (Hulit & Howard, 2001; Owens, 2001). They elaborate nouns by adding adjectives (e.g., big, pretty), demonstrative pronouns (e.g., this, that), quantifiers (e.g., some, a lot, two), possessives (e.g., my, your) and articles (i.e., a, the). Other examples of elaborated subjective noun phrases include “My doggie hiding,” “That boy bad” and “The ball gone.” Toddlers will modify both singular and plural nouns (Owens, 2001).

Toddlers rarely make errors when using adjectives to modify noun phrases (Owens, 2001). They appear to learn very quickly that adjectives cannot be used before pronouns or proper names (e.g., Davey).

In order to use adjectives to modify noun phrases, toddlers must first understand their meaning. Researchers have found that toddlers understand general dimensional terms (e.g., big/little) before more specific terms (e.g., tall/short) (Hulit & Howard, 2001). Within these pairs, toddlers understand the positive member (e.g., big, tall) of the set before the other half of the pair (e.g., little, short). Toddlers use context to interpret dimensional terms (Owens, 2001). For example, to interpret big and little, toddlers may compare two objects or judge whether an object is an appropriate size for the activity they are doing. Once they are understood, toddlers will modify noun phrases with dimensional terms (e.g., Big doggie).

Toddlers in the 25 to 36 month period appear to use color terms as adjectives before they understand their referents (Pan, 2005). For example, twenty-four-month-old toddlers, may say, “Green doggie” when referring to a black dog. As well, when asked, “What color is this?” these toddlers will answer with a colour term but usually it will be incorrect. When asked to group similar objects, these toddlers may group objects by colour.

Modifying Verb Phrases

Verb phrases in utterances become increasingly complex in the 25 to 36 month period (Weitzman, 1992). Between 27 and 30 months, toddlers master the present progressive (-ing) verb phrase elaboration (Hulit & Howard, 2001). They also begin to produce primitive infinitive verb phrases such as hafta, gonna and wanna, as in “I wanna go” (Hulit & Howard, 2001; Owens, 2001). Toddlers may use these semi-infinitives with a main verb (e.g., I gonna eat) or, more commonly, alone (e.g., I wanna) (Owens, 2001). At 30 months, toddlers also begin to produce negative forms of semi-infinitives (e.g., I won’t) (Hulit & Howard, 2001). The infinitive verb phrase “be going to” is used by many children at 33 months of age (Owens, 2001), while “have got to” is not used by most children until 36 months. Verb phrases also increase in complexity through the use of auxiliary verbs. For more information on the development of auxiliary verbs, see Auxiliary Verbs.

Toddlers also begin to use verb markers (e.g., -s) for tense (e.g., past, present) and number (e.g., one, many), increasing the complexity of the verb phrase (Owens, 2001). Initial development of verb markers appears to be on a word-by-word basis, with toddlers initially learning markers for the general verbs used first in the second year (e.g., makes). Toddlers gradually learn markers for more specific verbs (e.g., runs). With development of the present progressive, regular past and irregular past morphemes, toddlers are also able to use verbs to indicate the timing of events (Owens, 2001). Toddlers are able to indicate whether an event was in the past (e.g., “I jumped”) or present (e.g., “I digging”).

Toddlers used both transitive (e.g., want) and intransitive (e.g., run) verbs in the 13 to 24 month period (Owens, 2001). Transitive verbs require an object, whereas intransitive verbs do not. In the 25 to 36 month period, toddlers produce utterances in which transitive verbs were followed by a direct object (e.g., Baby want juice). Toddlers begin to use have and do as verbs in the 27 to 30 month period (Hulit & Howard, 2001).

Using Bound Morphemes

Another way in which toddlers’ utterances increase in length is through the use of bound morphemes. Morphemes are the smallest meaningful units of language and include open-class and closed-class words as well as bound morphemes which must be attached to an open-class word to be meaningful (Hulit & Howard, 2001). Bound morphemes include prefixes (e.g., “un-”), suffixes (e.g., “-ly), the possessive –‘s, plural –s, and verb markers (e.g., -ed). By the time they were producing two-word utterances, toddlers understood the meaning of some grammatical morphemes (e.g., -ing, -ed, plural –s) (Hoff, 2001) and may have been using some bound morphemes correctly in their utterances (e.g., -ing). However, it is not until the 25 to 36 month period, that the majority of bound morphemes begin to be used.

Using Morphemes to Determine Mean Utterance Length (MLU)

To describe the average length of a collection of toddlers’ utterances, researchers developed the variable, mean length of utterance or MLU. They use MLU to assess progress in, and to define periods of, toddlers’ language development (Owens, 2001). MLU has been found to be a reliable predictor of language complexity for English-speaking children up to a MLU of 4.0. However, it is only sensitive to language developments that result in an increase in utterance length. MLU is calculated based on a language sample of 50 to 100 utterances. Once the morphemes in each utterance are counted, researchers apply the following formula to determine MLU:

MLU =  Total number of morphemes 

           Total number of utterances


Between 13 and 26 months, toddlers typically have a MLU of 1 to 1.5 morphemes (Hulit & Howard, 2002; Owens, 2001). Toddlers between 27 and 30 months of age typically have a mean length of utterance (MLU) of 2.0 to 2.5 morphemes. These toddlers may be producing utterances one, two, three, four or more words in length. They are producing fewer single-word utterances and more multiple-word utterances than in the previous time frame (Hulit & Howard, 2001). Between 31 and 34 months, the range of toddlers’ MLU has increased to 2.5 to 3.0 (Hulit & Howard, 2001; Owens, 2001).

Brown's Fourteen Morphemes

Using MLU, Brown (1973) characterized the major language developments that occur as MLU increases, identifying six stages of development. Between 13 and 25 months, Brown described toddlers as being in Stage I. In this stage, MLU ranges between 1 to 1.5 morphemes and toddlers are learning to combine words for different meanings. Between 27 and 30 months, toddlers are in Stage II which is characterized by the appearance of grammatical morphemes which serve to modulate the meaning of simple sentences (Hulit & Howard, 2002; Owens, 2001). Brown (1973) identified fourteen morphemes for study. While all of these morphemes emerge between 27 and 30 months, most are not mastered during this time period. Toddlers are said to have achieved mastery for grammatical morphemes when they use it correctly 90% of the time in obligatory contexts (Hulit & Howard, 2002; Owens, 2001)

The fourteen morphemes have the following characteristics (Owens, 2001). First, these morphemes are phonetically minimal forms (e.g., the plural addition of “s”). Secondly, they are not stressed during speech. Third, these morphemes are not open-class words (i.e., nouns, verbs, adjectives, adverbs) but rather from closed-class (e.g., preposition or article) or a class with limited numbers. Fourth, their phonological construction may be different depending on the word to which they are attached (e.g., plural “s” has three different phonological forms). Finally, these fourteen morphemes develop gradually over time.

It is important to note that the information for these fourteen morphemes is for toddlers learning English. Morpheme development may be very different in other languages. For example, in Egyptian Arabic, plural marking is very complex and as a result, mastery may not be obtained until the teenage years (Owens, 2001).

Present progressive -ing.

The present progressive verb tense first began to emerge at the end of the second year (Hulit & Howard, 2002). While some children may have achieved mastery of this morpheme during that year, the age range of mastery of the present progressive –ing form ranges between 19 and 28 months (Hulit & Howard, 2001; Owens, 2001). The present progressive provides information about the timing of the action, informing the listener that the action is currently underway and is of temporary duration (Apel & Masterson, 2001; Owens, 2001). The present progressive verb tense is the earliest verb inflection acquired by toddlers learning English (Owens, 2001). Initially, toddlers express the present progressive tense without the auxiliary verb (e.g., Mommy running, Baby crying). This tense is used only with action verbs (e.g., run, eat) and not with verbs of state (e.g., need, know). Toddlers first use the present progressive with verbs that display a discrete end (e.g., drinking), rather than on verbs that describe a discrete event (e.g., falling). Toddlers rarely overgeneralize use of “-ing” to verbs of state.

In and on.

In and on are the next two morphemes studied by Brown (1973). These morphemes are fully mastered within stage II or by 30 months. For an in-depth discussion of these morphemes, see Prepositions.

Regular plural -s.

Some toddlers may have begun adding the plural –s before 24 months. The age of mastery for the regular plural is 27 to 33 months (Hulit & Howard, 2001; Owens, 2001). Toddlers will first produce this morpheme in short phrases (e.g., “More dogs”) and then in short sentences (e.g., “I want crackers”).

In the previous year, toddlers indicated more than one thing by using the word more (e.g., more cow) or a number (e.g., two cow) (Owens, 2001; Weitzman, 1992). Sometimes, they may not have marked the plural at all in their productions (e.g., “cow”). In the next stage of plural development, toddlers will mark the plural on selected, frequently used words (e.g., “dogs”). They then begin to mark the plural on many different nouns, which sometimes results in incorrect productions (e.g., foots). Toddlers produce few instances of overgeneralizations. In the final stage of plural development, toddlers differentiate regular and irregular forms (e.g., mouse and mice).

There are three different phonological forms for the regular plural: /s/, /z/ and /Iz/ (Owens, 2001). The voiceless plural marker, /s/, is used following voiceless consonants (e.g., boots). The voiced plural marker, /z/, is used following voiced consonants (e.g., beds). The plural marker, /Iz/, is used if the word ends in /s, z/ or “sh” (e.g., brushes). Toddlers first learn the rule for /s/, then for /z/ and finally /Iz/. These rules are acquired gradually. Forty-eight month-old toddlers may still be acquiring these rules.

Irregular past tense.

Irregular past-tense verbs are those that do not use the –ed ending (e.g., ate, drank) (Owens, 2001). Toddlers acquire a small subset of frequently-used irregular past-tense verbs in Stage II, including came, fell, broke, sat, and went. When learning the regular past tense –ed, toddlers may add that morpheme to verbs with irregular past tense (e.g., felled, eated). The age range for mastery of this morpheme is between 25 and 46 months.

Possessive.

Toddlers originally marked possession by words order and stress (e.g., Daddy hat) (Owens, 2001). They begin learning the possessive “s” between 27 and 30 months. Initially, they will use this morpheme with single animate nouns (e.g., Mommy’s). They mark possession on objects that can have different owners (e.g., clothing) before they mark possession on unalienable objects (e.g., body parts). Toddlers’ age range for mastery of the possessive is 26 to 40 months. However, they may not master the three phonological forms (i.e., /s/, /z/, /Iz/) until later.

Uncontractible copula.

When the verb “to be” is used as the main verb in an utterance, it is called the copula (Owens, 2001). In utterances, the copula may be followed by a noun, adjective, adverb, or prepositional phrase (e.g., Boy is sick). The copula is first mastered in utterances in which it is not grammatically correct to form a contraction (e.g., He is). The copula cannot be contracted when the response to a question omits redundant information (e.g., Who is here? Mommy and Daddy are). It cannot be contracted when it is the first or last word in a question (e.g., Is he sick?), in negative sentences in which not is contracted (e.g., The boy isn’t sick) and in the past tense (e.g., The boy was sick). Age of mastery for the uncontractible copula is between 27 and 39 months.

Articles.

The articles a and the are first produced in the 27 to 30 month period (Owens, 2001). The age of mastery for these morphemes is 28 to 46 months. Initially, due to their pronunciation, it may be difficult to determine which of these morphemes toddlers are using. Adults use the indefinite article, a, to indicate a non-specific reference or new information, while the definite article, the, is used to indicate a specific reference or old information. For example, adults may start a conversation about clothes with “I want to buy a new shirt” (i.e., a denoting new information) and continue it with “The shirt I liked best was green and blue striped” (i.e., the denoting old information).

Toddlers first use articles when naming (e.g., That’s a dollie) (Owens, 2001; Weitzman, 1992). Initially, the article a predominates. Use of the definite article for referencing develops later (e.g., The dollie crying).

Regular past.

The regular past verb tense, -ed, is mastered between 26 and 48 months (Owens, 2001). As mentioned previously, toddlers may initially overgeneralize this morpheme to irregular past-tense verbs (e.g., comed). Toddlers are more likely to use this morpheme on verbs that describe a discrete event (e.g., drop). There are three phonological variations of the regular past tense. The voiced form, /d/, is used following voiced consonants (e.g., begged), while the voiceless form, /t/, is used following voiceless consonants (e.g., walked). The final irregular form, /Id/, is used following /t/ and /d/ (e.g., batted) and is acquired last.

Third person singular marker: Regular and irregular.

In English, the regular form of this marker (-s) is only used for the third person singular (e.g., He runs) (Owens, 2001). Similar to both the plural and possessive morphemes, there are three phonological variants. There are only a few English verbs that mark third person singular irregularly (e.g., do – does, have – has). The age of mastery for this morpheme ranges between 26 and 46 months.

Uncontractible auxiliary.

The uncontractible auxiliary refers to the verb “to be” when it is used as an auxiliary or helping verb (Owens, 2001). This morpheme is followed by a verb in utterances and is uncontractible in past tense (e.g., She was running). Other conditions in which the auxiliary verb “to be” is uncontractible include when it is the first or last word in a sentence, when the negative is contracted and when known information is omitted in response to a question (see Uncontractible copula for examples). The age of mastery for the uncontractible auxiliary is between 29 and 48 months.

Contractible copula.

The uncontractible auxiliary refers to the verb “to be” when it is used as an auxiliary or helping verb (Owens, 2001). The contractible auxiliary is mastered between the ages of 30 and 50 months. An example utterance containing the contractible auxiliary is “Daddy is drinking juice.” The development of the contractible copula and auxiliary is similar.

Contractible auxiliary.

The uncontractible auxiliary refers to the verb “to be” when it is used as an auxiliary or helping verb (Owens, 2001). The contractible auxiliary is mastered between the ages of 30 and 50 months. An example utterance containing the contractible auxiliary is “Daddy is drinking juice.” The development of the contractible copula and auxiliary is similar.

Developing Different Sentence Forms

In the 13 to 24 month period, toddlers expressed negation, questioned and made demands primarily by modulating intonation and pitch (Tager-Flusberg, 2005). During Brown’s Stage III (MLU 2.0 – 2.5) which occurs between 30 and 34 months, toddlers acquire more adult-like sentence structures for negatives, questions, imperatives, and declaratives (Hulit & Howard, 2001; Owens, 2001). In the 25 to 36 month period, toddlers use a combination of pitch, intonation and syntax to express these different forms.

Negative Sentences

Three main periods in the acquisition of negatives have been identified (Hulit & Howard, 2001; Owens, 2001; Tager-Flusberg, 2005). In the first period, toddlers create negative sentences by inserting a negative marker at the beginning or end of a statement (e.g., No house, No go bed, Bunny no, No Daddy go work). The final example is less commonly produced than the other constructions and is usually used to express rejection of a proposed course of action (Owens, 2001). In the first period, toddlers use negation to express nonexistence (e.g., No cookie), rejection (e.g., No nite-nite), and denial (e.g., Not doggie). They first use negative utterances to indicate nonexistence, then rejection and finally to indicate denial (Owens, 2001). Toddlers also insert negatives in statements as a conversational device (Owens, 2001). For example, toddlers may say “No Daddy” in response to a question. This structure is typically produced by children between the ages of 25 and 28 months in the latter half of Brown’s Stage I and beginning of Brown’s Stage II, when MLU ranges from 1.5 to 2.25 (Hulit & Howard, 2001; Owens, 2001). As toddlers do not differentiate between no and not in their utterances, situational cues (e.g., intonation, pitch, body language) are important for interpreting meaning (Hulit & Howard, 2001; Owens, 2001).

In the second period, toddlers create negatives by inserting the negative marker next to the verb, as in the following example, “I no want cookie” (Hulit & Howard, 2001; Tager-Flusberg, 2005). This form of negation is produced when MLU ranges from 2.25 to 2.75 (later Stage II and early Stage III) between the ages of 28 and 32 months (Hulit & Howard, 2001; Owens, 2001). During this time, toddlers are using no, not, can’t, and don’t interchangeably. Individual preferences and caregiver use appear to guide which negative element is used by toddlers (Owens, 2001).

In the third period, toddlers’ negative sentences are more adult-like, as they now contain auxiliary verbs (Hulit & Howard, 2001; Tager-Flusberg, 2005). For example, toddlers may say “Mommy is not home” or “Baby don’t cry.” Toddlers begin producing adult-like negative sentences when they are between 32 and 36 months of age when MLU ranges from 2.75 to 3.5, corresponding to late Stage III and early Stage IV (Hulit & Howard, 2001). In this stage, toddlers may begin using won’t interchangeably with no, not, can’t, and don’t (Owens, 2001).

Questions

In the earliest period of interrogative development, toddlers use rising intonation to indicate that they are asking a question (e.g., Baby tired?) (Apel & Masterson, 2001; Hulit & Howard, 2001; Tager-Flusberg, 2005). This stage occurs when MLU ranges between 1.75 and 2.25 (later Stage I and early Stage II) between the ages of 25 and 28 months (Hulit & Howard, 2001; Owens, 2001). This period can be characterized by three types of structures: word + intonation, What + noun phrase + (doing) (e.g., What doggie (doing)?) and where + noun phrase + (going) (e.g., Where ball?) (Owens, 2001). In the latter two constructions, doing and going are understood by listeners but not produced. What and where questions may be common because they relate to things in toddlers’ immediate environment and are used for naming and locating (Hulit & Howard, 2001; Owens, 2001). As well, what and where questions are frequently used by caregivers.

In the second period, toddlers continue to use intonation to ask yes/no questions, ask what and where questions more frequently and begin to ask why questions (Hulit & Howard, 2001; Owens, 2001). This period is associated with late Stage II and early Stage III when MLU ranges from 2.25 and 2.75. Toddlers at this stage are between 26 and 32 months of age. Questions are increasingly complex and contain both a subject and verb phrase but do not usually contain an auxiliary verb (e.g., Where puppy hide? Why he do that?). In cases where toddlers produce questions that contain auxiliary verbs, they do not invert them as per adult rules, rather they say, for example, “You is eating?”

n the third period, toddlers produce questions that contain auxiliary verbs and invert the auxiliary and subject according to adult rules (e.g., Is she going home? Where did puppy go?) (Hulit & Howard, 2001). Yes/no questions are common and may be produced using either the copula or an auxiliary verb with the subject and auxiliary verb reversed (e.g., Is daddy making cake?). Toddlers may produce wh-questions with or without auxiliary verbs (e.g., What daddy do? or What is daddy doing?). Wh-questions are the first type of questions to be inverted (Owens, 2001).

Toddlers acquire what, where, and who questions before why, when, and how questions (Tager-Flusberg, 2005). What, where and who questions are both easier to understand and easier to respond to. To understand why, when and how questions, toddlers must understand more abstract concepts, such as time, causality and manner, that develops later. As well, these later-developing wh-questions require full sentence responses unlike what, where and who questions that require only single word or short phrases responses. At 24 months, the number of questions asked by toddlers and their vocabulary size are positively correlated (Owens, 2001).

Imperative Sentences

Imperatives are used to request, demand, or command that the listener perform some act (Hulit & Howard, 2001; Owens, 2001). Between 18 and 30 months of age, toddlers use body language and prosody to indicate these functions. For example, to request to go outside, a toddler may gesture towards the door while pulling on his caregiver’s hand and saying “Go yard.” Such utterances are declarative sentences produced without the subject. True imperatives are not produced until 31 months of age. In true imperatives, the subject, “you,” is implied and the verb is uninflected (e.g., Pick me up).

Toddlers’ understanding of imperatives is also developing. Twenty-four to thirty-six-month-old toddlers understand two-step directions (Weitzman, 1992). An example of a two-step direction would be “Go get your baby and put it to bed.”

Declarative Sentences

Initially, toddlers’ declarative sentences are of the type agent + action (e.g., Mommy do) or action + object (e.g., Eat cookie) (Owens, 2001). Gradually, declarative sentences increase in complexity, as the number of elements increases. By 30 months, toddlers acquire the basic subject + verb + object, as in the example “Mommy read book,” and subject + copula + complement formats, as in “Dolly is pretty” (Hulit & Howard, 2001; Owens, 2001). Acquisition of closed-class words such as auxiliary verbs and prepositions allows toddlers to produce declaratives with the following structures: subject + auxiliary + verb + object and subject + auxiliary + copula + complement (Owens, 2001). Toddlers produce the former before the latter. Examples of these declarative structures are as follows, “Boy is going school” and “Daddy won’t be happy,” respectively.

Toddlers’ understanding of active and passive declarative sentences develops over time. Toddlers younger than 30 months of age understand active sentences such as “The dog is chasing the cat” (Owens, 2001). However, these toddlers will interpret passive sentences such as “The cat was chased by the dog” as if the first noun was the subject and the second noun was the object (i.e., as if the cat was chasing the dog). Toddlers do not correctly interpret passive sentences until they are 48 months or older. Researchers have found that for active sentences, production may precede comprehension (Hulit & Howard, 2001).

Developing Deixis

Deixis is a process in which the meaning of a word relies on the context. For example, the meaning of the word I changes depending on who is speaking. Toddlers develop an understanding of deixis gradually (Owens, 2001). They first demonstrate understanding of deixis relative to the pronouns I, you, and me.

There are three phases in the development of spatial deictic terms such as here and there (Owens, 2001). Initially, toddlers will use these terms indiscriminately to direct attention or reference. Thirty-month-old toddlers will use these terms in association with a gesture to indicate meaning. This and that continue to be used indiscriminately until 48 months of age. Toddlers interpret these terms as near the speaker, far from the speaker, near them or far away from them. Toddlers seem to prefer to use themselves as the point of reference. In the second phase, toddlers use this and here correctly but overgeneralize these terms when they should use that and there. Toddlers may correctly use all four terms when using themselves as the reference point. In the final phase of development, the deictic point of reference is mastered. Age of mastery varies depending on the term, with some contrasts not understood until adulthood.

Developing Narratives

Between 25 and 36 months, toddlers begin to produce self-generated narratives (Hulit & Howard, 2001; Owens, 2001). A narrative may be described as a series of sentences conveying information about events or experiences in an orderly sequence in which the speaker is exclusively responsible for conveying the message (Hulit & Howard, 2001). Therefore, in order to produce narratives, toddlers must understand sequences (Owens, 2001). Toddlers first develop this understanding in the context of routines. Even before they produced their first words, toddlers understood that, in sequences, some actions occur at the beginning, others in the middle and others at the end. Although 24-month-old toddlers understand routines and some event sequences, they will not typically be able to accurately describe sequences of events until 48 months of age. Toddlers first produce protonarratives. To organize their narratives, toddlers use centering and chaining.

Protonarratives

Between 24 and 42 months of age, toddlers produce protonarratives (Hulit & Howard, 2001; Owens, 2001). A protonarrative is “a primitive story about something that has happened to the child” (Hulit & Howard, 2001, p. 196). The frequency with which toddlers produce protonarratives doubles between 24 and 30 months of age (Hulit & Howard, 2001; Owens, 2001). In comparison to conversation, protonarratives contain five times as much evaluative information (e.g., “I cried,” “I didn’t like it”) (Owens, 2001).

The topics of 25- to 36-month-old toddlers’ protonarratives are usually specific, often distressing, events. Before beginning their protonarrative, toddlers do not orient their audience to their topic (Owens, 2001). Protonarratives have a vague plot and lack easily identifiable beginnings, middles and ends. Participants, time and location may not be identified in protonarratives. As a result, listeners may have difficulty understanding these early narratives (Weitzman, 1992).

Strategies for Organizing Narratives: Centering and Chaining

Toddlers follow two strategies when structuring early narratives: centering and chaining (Hulit & Howard, 2001; Owens, 2001). Initially, toddlers organize narratives by centering. Following this strategy, toddlers create a narrative around a central theme (Hulit & Howard, 2001). Each object or action mentioned relates to the theme, although this relationship may seem somewhat tenuous to the listener. Between 25 and 36 months, toddlers use centering to organize most protonarratives.

Early narratives created using a centering strategy may also be referred to as a “heap” (Hulit & Howard, 2001; Owens, 2001). Heaps are a set of unrelated utterances connected by a common originating stimulus. Utterances may be grammatically similar and have a basic sentence structure. Information is added with each successive utterance. As there is little or no sequencing, no theme, no story line and no cause and effect in heaps, changing the sentence order does not affect meaning. Heaps may be used to describe a scene. There is no overall meaning in toddlers’ heaps. Hulit and Howard (2001) provide the following example of a heap: “Mommy sit here. Baby go “Waa!” Kitty go “Meow!” Doggie play ball.”

Toddlers then begin to produce centering sequences (Owens, 2001). The topics of these centering sequences are “events linked on the basis of similar attributes or events that create a simple but meaningful focus for a story” (Owens, 2001, p. 290-291). As organization is not temporal, changing the sentence order does not affect meaning. Toddlers use prosody and gestures extensively while telling early narratives. Owens (2001) provided this example of a centering sequence: “I ate a hamburger (Mimes eating). Mommy threw the ball, like this. Daddy took me swimming (Moves hand, acts silly). I had two sodas” (p. 291).

With chaining, events share one or more features in common with each event in the narrative, logically building on the preceding one. By 36 months of age, toddlers may be using both centering and chaining strategies when building narratives.

Gotzke, C. & Sample Gosse, H. (2007). Research Narrative: Listening, Vocalizing and Interacting 25 - 36 Months. In L.M. Phillips (Ed.), Handbook of language and literacy development: A Roadmap from 0 - 60 Months. [online], pp. 1 - 8. London, ON: Canadian Language and Literacy Research Network. Available at: Handbook of language and literacy development