The morphological structures that children acquire during their childhood, and even up to the early school years, are: determiners (a, the), -ing inflection, plural -s, auxiliary be, possessive -s, third person singular -s, past tense -ed).
When children start using them they tend to overgeneralize the rules and project them upon all the words in the language, including irregulars. For example: if a child knows the -ed (past tense) there is a possibility that they'll say "I eated"(Man-mans cat-cats). These errors result from overgeneralization of rules.
This overgeneralization is very noticeable, in fact, children do that in less than 25 percent of the time at any point before reducing that percentage. Then they improve their mastery, which can be tested in various ways, such as the "wug test" (Berko, 1958).
Children often figure out quickly frequent irregular verbs, such as go and buy rather than less common ones, such as win. This suggests that children must hear the word several hundred times before they are able to use it correctly.
This development of bound morphemes is similar in order among children, for example: -ing is acquired before the article the. The interesting part though is that parents tend to use a different order while speaking to their kids, for example, parents use the article 'the' more frequently than -ing. Meaning, other factors determine the order of acquisition, such as:
- Morphemes that come at the end of an utterance are remembered better.
- Children seem to remember morphemes such as –ing better because they contain their own syllables rather than single consonant morpheme, such as plural -s.
- Affixes with more than one meaning are more difficult to acquire, e.g., -s functions both as plural noun and singular third.
As it comes to word formation processes such as derivation and compounding, the earliest derivational suffixes to show up in children's speech are those they hear adults use most frequently. (-er as the *'doer' of the action such as walker.) When it comes to compounds, children first make up names for agents and instruments that they don't know by a pattern (N-N), though some of them do not follow the pattern (*cutter grass for grass cutter). Then, they might have the right structure but the words are inappropriate since English already has words with the intended meaning such as car-smoke = exhaust. This process points to a preference for building words from other words, thus place less demand on memory than learning an entirely new word for each concept.
The development of syntactic structures follows a particular pattern and reveals much on the nature of language acquisition, which has several stages. According to O'Grady and Cho (2011), the first stage, occurring between the ages of 12–18 months, is called "one-word stage." In this stage, children cannot form syntactic sentences and therefore use one-word utterances called "holophrases" that express an entire sentence. In addition, children's comprehension is more advanced than their production abilities. For example, a child who wants candy may say "candy" instead of expressing a full sentence.
The following stage is the "two-word stage" in which children begin to produce "mini-sentences" that are composed of two words, such as "doggy bark" and "Ken water" (O'Grady & Cho, 2011, p. 346). At this stage, it is unclear whether children have an understanding of underlying rules of the language such as syntactic categories, since their "mini-sentences" often lack distinction between the categories. However, children do exhibit sensitivity to sentence structures and they frequently use appropriate word order.
After several months of speech that is restricted to short utterances, children enter the "telegraphic stage" and begin to produce longer and more complex grammatical structures (O'Grady & Cho, 2011, p. 347). This stage is characterized by production of complex structures as children begin to form phrases consisting of a subject and a complement in addition to use of modifiers and composition of full sentences. Children use mostly content words and their sentences lack function words. For example, a child may say "fill cup water," instead of saying, "Fill my cup with water." Subsequently, language acquisition continues to develop rapidly and children begin to acquire complex grammar that shows understanding of intricate linguistic features, such as the ability to switch the position of words in sentences.
Throughout the process of syntactic development, children acquire and develop question structures. According to O'Grady and Cho (2011), at the early stages of language acquisition, children ask yes-no questions by rising intonation alone as they develop awareness to auxiliary verbs only at a later stage. When auxiliary verbs make their appearance, it takes children a few months before they are able to use inversion in yes-no questions. The development of WH- questions occurs between the ages of two and four, when children acquire auxiliary verbs that then leads to the ability to use inversion in questions. However, some children find inversion easier in yes-no questions than in WH- questions, since the position of the WH- word and the auxiliary verb both must changed (e.g., "You are going where?" instead of "Where are you going?").
Syntactic development and morphological development
Syntactic development involves the ways that various morphemes are ordered or combined in sentences. Morphemes, which are basic units of meaning in language, get added as children learn to produce simple sentences and become more precise speakers. Morphemes can be whole words (like "happy") or parts of words that change meaning of words ("un"happy). Brown proposed a stage model that describes the various types of morphological structures that are developed in English and the age range within which they are normally acquired.
Stage I: From 15–30 months, children start using telegraphic speech, which are two word combinations, for example 'wet diaper'. Brown (1973) observed that 75% of children's two-word utterances could be summarized in the existence of 11 semantic relations:
- Attributive: 'Big house'
- Agent-action: 'Daddy hit'
- Action-object: 'Hit ball'
- Agent-object: 'Daddy ball'
- Nominative: 'That ball'
- Demonstrative: 'There ball'
- Recurrence: 'More ball'
- Non-existence: 'All-gone ball'
- Possessive: 'Daddy chair'
- Entity + Locative: 'book table'
- Action + Locative: 'go store'
Stage II: At around 28–36 months, children begin to engage in the production of simple sentences, usually 3 word sentences. These simple sentences follow syntactic rules and are refined gradually as development continues. The morphological developments seen in this age range include use of present progressive (-ing endings), the prepositions "in" and "on", and regular plurals (-s endings).
Stage III: Around 36–42 months, children continue to add morphemes and gradually produce complex grammatical structures. The morphemes that are added at this age include irregular past tense, possessive ('s), and use of the verb 'to be' (It is, I am, etc.).
Stage IV:Around 40–46 months children continue to add to their morphological knowledge. This range is associated with use of articles (a or the), regular past tense (-ed endings), and regular third person speech (He likes it).
Stage V: Around 42-52+ months children refine the complex grammatical structures and increase their use of morphemes to convey more complex ideas. Children in this stage use irregular third-person speech, the verb 'to be' as an auxiliary verb (She was not laughing), and in its contraction forms (It's, She's, etc.).
