Early language development: From single words to word combinations

Abstract

The language development of one child from single words to multiword utterances was studied longitudinally using naturalistic observations to examine the relation between vocabulary growth and syntactic development. Between the ages of 1;2(0) and 1;9(11), for a period of 32 weeks, the subject's new words were recorded daily and utterances were transcribed during several weekly sessions. Single words were analyzed using rates of new words, word types, and word tokens. Word combinations were analyzed using MLU and rates of new combinations, combination types, and combination tokens.;The shape of the cumulative weekly acquisition of new words was curvilinear. The rates of production of new words, word types and word tokens increased abruptly toward the end of the study; however, the slope of the rates was steepest for word tokens, less steep for word types, and least steep for new words. After the vocabulary spurt, new words declined precipitously, word types decreased slightly, and word tokens rose continuously. As research advanced, ratios of word types to word tokens approached zero.;The rates of production of new combinations, combination types, and combination tokens rose suddenly toward the end of research, and advanced continuously during the last weeks of the study. MLU showed a pronounced and sustained rise during the last weeks of research. The steep rise in the number of combinations contrasted with the smooth increase in MLU. Throughout the study, the ratios of new combinations to combination types remained close to one.;Although the rates of production of new words and new combinations increased abruptly toward the end of research, the former started to increase earlier than the latter. After the vocabulary spurt, an inverse relationship between new words and combinations occurred. A pronounced decline in rate of new words coincided with an extended increase in rate of combinations. It was suggested that a child's preoccupation with constructing word combinations results in the temporary neglect in learning new words.;Combinations exhibited several general pattern frames which were repeated frequently suggesting that syntax was achieved through the repetition of patterns and not through the repetition of specific combinations.