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

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Developmental Milestones

Vocabulary Development (0-60 Months)click to print Print

Written by: Andrew Biemiller, Ontario Institute for Studies in Education, University of Toronto

The first five years of life are a very important time for children's language acquisition and development. By the time children are old enough to start school, they have already learned much of their language. Sometimes, however, there are differences in children's vocabulary development. Differences are expected but there are typical developmental patterns and they ate presented next. Related information is also available under Developmental Milestones for Children's Literature, Reading, and Speech Language Development.

0-12 Months During this period, infants and toddlers children learn to discriminate phonemes (the sound features used to recognize words).

By the end of this period, children may understand up to 50 words, mainly referring to objects or actions.
13-15 Months Toddlers begin to understand a number of new words each month, probably because the words are explained.

Perhaps 70 to 150 word meanings are now understood.

Many more words are understood than are spoken by the toddlers.

Most words learned continue to refer to objects or actions.
16-18 Months New word meanings are learned more rapidly.

An average of 70 new word meanings is acquired each month. However, only about 50 words are likely to be said by the child.

By 18 months of age, an average of 350 words may be understood. However, most words learned are still mainly words that refer to objects or actions.
19-24 Months
Children continue to add an average of 70 new words each month.

Thus by 24 months, children understand an average of 600-700 words.

Some newly learned words are now adjectives.

During this period, children begin to combine 2 words, for example, big mommy; or more milk!)

They clearly also understand 2 word phrases, for example child is told to "kiss (the) truck" and child carries out a request to "kiss" a toy truck.
25-36 Months During the third year, in addition to more nouns, action words, and modifiers, children learn some "relational" terms; including prepositions and spatial relational terms (e.g., under, there) and also some "action/event" terms (e.g., bring, drop, listen, remember, breakfast) and "description" terms or adjectives (e.g., asleep, bad, heavy, long). Many adjectives are relational, for example big vs. little.
37-60 Months Many children begin to acquire verbally-defined meanings in addition to the concrete words learned thus far.

Children learn verbally-defined words such as clever, weather, amaze, meaning.

By 60 months of age, knowledge of verbally-defined meanings distinguishes children making average progress compared to children making below-average progress.

Note that average children continue to add around 70 word meanings to their vocabulary per month.

Biemiller, A. (2009). Vocabulary Development: Developmental Milestones. In L.M. Phillips (Ed.), Handbook of language and literacy development: A Roadmap from 0 – 60 Months. [online], pp. 1-2. London, ON: Canadian Language and Literacy Research Network. Available at: Handbook of language and literacy development