The purpose of this article is to review research on the acquisition of first words in children who are developing typically, children who are late talkers, and children with developmental delays. Clinical applications of the research, including assessing early vocabularies using parent report instruments, choosing a first vocabulary for children with language delays, and using focused stimulation and milieu teaching during storybook and pretend play activities will be discussed.
and cognitive delays.
The rest of his history is unremarkable.
Max has no real, single words.
Make a list of the first 10 to 12 words you would target in intervention.
The vocabulary of the first 50 words has long intrigued child language researchers. Initial research in this area used vocabulary diaries and focused on individual children who were developing typically (e.g., Bloom & Lahey, 1978; Nelson, 1973). In more recent years, use of parent-completed vocabulary checklists has allowed researchers to collect data from larger populations of children, with and without language delays, thereby drawing more generalizable conclusions (e.g., Fenson et al., 1994; Lederer, 2006a; Rescorla, Alley, & Christine, 2001). As a result, we now have information on the first words acquired by typically developing children, late talkers, and children with language and cognitive delays. This paper will review the research on first words in each of these three populations and discuss clinical applications of the research to assessment and intervention.
First Words in Children Developing Typically
First words typically appear between 10 and 16 months. Children learn .81 new words per day before 24 months and typically master 50 words between 18 and 24 months, with 24 months representing the outer limits of normal (Fenson et al., 1994). The average two-year-old has a vocabulary of 200 to 300 words (Owens, 2001). Between 24 and 30 months, children acquire 1.64 new words per day (Fenson et al., 1993).
In terms of lexical diversity, most children are "noun-lovers" (i.e., referential style), which has been attributed to parental labeling. However, a continuum exists between "noun lovers" and "noun leavers" (i.e., expressive style), the latter considered a more peer-influenced style. The vocabularies of noun-lovers appear to grow initially at a faster rate than those of children with more of a balanced lexicon (see Owens, 2001, for a review).
In her seminal longitudinal study, Nelson (1973) found that more than half of the first 50 words (65%) acquired by the 18 typical children in her study are nouns, called nominals or substantive words. The balance of the first lexicon is non-nouns often termed relational words. Nelson further categorized relational words as "actions," "modifiers," "personal-social words," and "function words." She defined the terms as follows:
- Nominals (65%): general and specific nouns (animals, foods, toys, family)
- Actions (13%): words that describe, demand, or accompany an action or that express attention or demand attention to action; in early language acquisition these may not be true verbs, such as "hi," "bye," "up," "down," "bath"
- Modifiers (9%): words that refer to properties or qualities (attribution, state, locative state, possession)
- Personal-Social Words (8%): words that express social relationships ("yes," "no," "thank you," "please")
- Function Words (4%): words relating to other words, such as question words
(Nelson, 1973, pp. 16-17)
Nelson's definition of actions includes words that suggest action, but are not true verbs. Instead, she codes these words as action greetings (e.g., "hi," "bye") and locatives/prepositions (e.g., "in," "on"). These are commonly referred to as protoverbs. This issue of true verbs will be explored in each study discussed hereafter.
During the development of the MacArthur Communicative Development Inventory (CDI; Fenson et al., 1993), Fenson and his colleagues (1994) collected vocabulary data from over 1800 typically developing children and identified at what age (in months) each of 680 specific vocabulary words were spoken by at least 50% of the participants. Like Nelson (1973), the majority of the first 50 words (produced by at least 50% of the sample by 18 months) were nominals (66%) with 34% relational words. Of the relational words, 12% were action words (again, protoverbs, not true verbs) and 22% were made up of exemplars from the other three categories.