Usually by ten months of age the child succeeds in using one word significantly. By twelve months of age the average child has a vocabulary of three or four distinguishable words. But great individual differences are noted by all careful observers depending on intelligence, health, encouragement, opportunity and environmental influences. I recently saw a boy of three years who had a vocabulary of 100 words at twelve months of age, but certainly by three years he had a bad stammer!
A good cultural environment, a good pattern of adult speech, and normal encouragement facilitates language development. High intelligence is correlated with early speech development. Feeble-minded children may not start to talk until nearly three years of age, and their vocabulary and mastery of language forms grows very slowly.
Excellent health and great physical activity may be conducive to slowness in speech development because the child tends to devote more of his time and energy to learning to walk and to acquiring other physical skills. Girls tend to talk earlier and their vocabulary develops more rapidly than that of boys. They tend to maintain their advantage through all stages of linguistic development.
After the first word has been spoken the child’s vocabulary grows very slowly, one or two words being made to act as maids of all work, assuming a different meaning according to the context. After eighteen months, however, it begins to increase rapidly. The following norms were obtained by Smith from Carefully standardized vocabulary test:
It is interesting to compare these figures with those obtained by Term an from a test list of 100 words selected to represent adequately and fairly the contents of the ordinary dictionary. He obtained his figures by determining the standards for different years by the vocabulary reached by 60 to 65 per cent of the subjects at the various mental levels.
At first the child’s attempts at verbal expression and communication are “sentence words,” or “one-word sentences.” “Up” means “Put me up there now.” “Mama” may mean “Mother come here quickly.”
“No” means “Take it away at once. I don’t like it.” This economical form of language, usually accompanied by gesture and facial expression, can be surprisingly effective, and may satisfy the child for many months.
By two and a half years a slightly more complex type of sentence may be expected, but children vary tremendously in this respect. I know one little girl of twenty-two months who remarked clearly and precisely on seeing the new moon, which had changed from white to yellow as the darkness fell, “Look! The moon’s got a light in it.”
The following norms obtained by Smith from a study of 124 children show how the sentence gradually increases in size and complexity.
In general it is found that after interjections, nouns and verbs are the most popular parts of speech for the young child. At first he may refer to himself by name, “John does it,” but gradually personal pronouns appear at about the end of the second year.
“John do it” becomes “Me do it,” and then “Let me do it,” or “I can do it.” Adverbs, then adjectives soon begin to appear more frequently, and conjunctions, prepositions and relational elements tend to appear last.
Language, therefore, tends to grow from the simpler forms to the more complicated and from crude and confused expression to the subtle and more defined.
Children who are brought up in institutions tend to talk later and to have a more limited vocabulary than children brought up in a more favorable environment who receive more individual attention.
Children learn readily from each other except twins, who are generally slow in language development, probably because they learn to understand each other so quickly by means of gesture, tone and a few words, usually unintelligible to adults.
Stimulation from adults and a high cultural level of home background are conducive to good speech development. Very intelligent children, who use abstract concepts probably more than practical concepts, tend to employ words a great deal, and acquire new ones rapidly.
Over-pressure, or the reverse, lack of encouragement, are both harmful to good speech development. The former often induces a stammer, and the latter slows up language development.
A limited environment with little opportunity for new experiences prevents rapid acquirement of new words. Persistence of baby talk is usually due to excessive attention being paid to it by adults, or the child may find it the best way of ensuring his mother’s interest. As soon as a child is able to pronounce words correctly he should be encouraged to do so.
The pre-school period from two to five years has been called the golden age of language. Interest in learning to speak, in acquiring new words, and delight in asking questions are commonly found.