Babbling and Early Words

Early words are produced by the child in expected contexts, and hence are recognized by familiar listeners as linguistic units conveying meanings. In 1999 Esther Dromi distinguished between comprehensible and meaningful words. Comprehensible words are phonetically consistent forms resembling adult words that caregivers understand, but that do not yet convey referential meanings. Meaningful words are symbolic, arbitrary, and agreed-upon terms of reference. Considerable variation exists in both the age of speech onset and the rate of early lexical development. Large-scale questionnaire data reported in 1994 by Fenson and his colleagues for English-speaking typically developing children, cited the range of vocabulary size for twelve- to thirteen- month-olds at 0 to 67 different words, and for eighteen- to nineteen-month-olds at 13 to 471 different words. In 2000 Maital and her colleagues reported very similar figures for Hebrew.

Early words are constructed from a limited set of consonants, mainly stops, nasals, and glides. Syllable structures in these words are usually CV, CVC, or CVCV. Several researchers found that during the first few months of lexical learning, many new words are composed from segments that the child is already using in babbling. A number of researchers have proposed that patterns of lexical selection and avoidance reflect the child's production capabilities. When productive vocabularies contain more than a hundred different words, the influences of phonology on the lexicon decline. Nevertheless, children who have relatively larger lexicons of single words also show larger inventories of sounds and syllable structures than children with smaller productive lexicons. Precocious word learners have much larger phonetic inventories than typically developing children at age eighteen months. The major semantic achievement in the first few months of vocabulary learning is the ability to use words referentially. Martyn Barrett and Esther Dromi, who independently carried out detailed longitudinal analyses of repeated uses of the same words over time, have argued that some early words show referential use from their outset, while other words are initially produced only in very specific contexts. Throughout the one-word stage, the phonology of words improves, and meanings become symbolic and arbitrary. A word initially produced in just one situation is now uttered in a much wider range of contexts, until it becomes completely context free and referential. As words become conventional tools for expressing meanings, the amount of pre-speech vocalizations declines and gradually disappears.