Most parents can hardly wait for their baby to say its first word. This usually happens between nine months and a year. From about two years, the child should be able to use simple phrases, and by three he should be able to use full sentences. By four, he should be fully able to talk, although he may still make grammatical errors. By five, he should have acquired basic language.
According to Wood, language acquisition takes place in six consecutive stages:
The prelinguistic stage
During the first year of life, the child is in a pre-speech stage. Developmental aspects related to speech would include the development of gestures, making adequate eye contact, sound repartee between infant and caregiver, cooing, babbling, and crying. Examples of such prespeech sounds would be dadadada, mamamama and waaaah.
The holophrase or one-word sentence
The child usually reaches this phase between the age of 10 and 13 months. Although the child tends to utter a single word at a time, its meaning is also supplemented by the context in which it takes place, as well as by nonverbal cues. An example of such a one-word sentence would be a child leaning over the edge of his cot and pointing to his bottle while laughing and saying “botty” in a commanding way. An adult in the situation could well interpret the child’s holophrase as meaning, “Give me my bottle immediately (so that I can throw it over the edge of the cot again and you can pick it up).” Another example would be “Dada”, which could mean “Daddy, please come to me.”
The two-word sentence
By 18 months the child reaches this stage. His or her “sentences” now usually comprise a noun or a verb plus a modifier. This enables the child to formulate a sentence that may be either declarative, negative, imperative or interrogative. Examples of such “sentences” are:
“Doggy big” (declarative)
“Where ball” (interrogative)
“Not egg” (negative)
“More sugar!” (imperative)
Once again, if the two-word sentence is supported by the situation as well as by nonverbal communication, it could have quite a complex meaning.
The child reaches this stage between the age of two and two and a half. Grammatical morphemes in the form of prefixes or suffices are used when changing meanings or tenses. Furthermore, the child can now form sentences with a subject and a predicate. Using the examples which were listed in the previous stage, the sentences could now be the following:
“Doggy is big”
“Where is ball?”
“That is not egg”
“I want more sugar”
“I catched it”
Ironically, in the last two examples, the linguistic errors are clear indications that the underlying grammatical principle was understood. The child’s sentences are still telegraphic although they may be quite long. An example of such a multiple-word sentence is: “People mustn’t walk street – people must walk pavement.” This specific sentence was used by a very bright 18-month-old child, which implies that these language developmental levels can be reached at an earlier age or at a later age than was indicated above. The extent and quality of the mediated language experience which the child receives are therefore of the utmost importance.
More complex grammatical structures
Children reach this stage roughly between two and a half and three years of age. They use more intricate and complex grammatical structures, elements are added (conjunction), embedded and permuted within sentences, and prepositions are used. Wood gives the following examples in this regard:
“Read it, my book” (conjunction)
“Where is Daddy?” (embedding)
“I can’t play” (permutation)
“Take me to the shop” (uses preposition of place)
Adult-like language structures
The five to six-year-old child reaches this developmental level. Complex structural distinctions can now be made, such as by using the concepts “ask/tell” and “promise” and changing the word order in the sentence accordingly. Examples are:
“Ask her what time it is.”
“He promised to help her.”