ABSTRACT
Childrens understanding and production of their first words is undeniably one of the most heralded achievements in early development. The onset of language officially marks the transition from £<in fancy” (which derives from the Latin root infans, meaning “unable to speak”) to early childhood, and radically alters the child s social world. Words enable children to share meanings with others and to participate in cultural learning in unprecedented ways. The fact that all normally developing children acquire language suggests that there exist universal properties that support childrens language de velopment, including the opportunity to communicate with others and direct and indirect access to analyzable language models (e.g., Meisel, 1995). Nonetheless, children vary enormously in the course of their language growth in terms of how quickly they achieve specific milestones, their recepti ve and productive vocabulary sizes, and in their eventual levels of competence in syntactic, semantic, and pragmatic aspects of language (Bloom, 1993; Hoff-Ginsberg, 1997; Tamis-LeMonda & Bornstein, 2002). For example, some children speak as early as 8 months while others express their first words several months later (e.g., Acredolo, Goodwyn, Horobin, & Emmons, 1999; Dapretto & Bjork, 2000). Blooms (1993) research on the language achievements of 12 children illustrates the substantial variation in the age of onset of childrens first words. Although children expressed their first conventional words (i.e., adult word forms) at the start of the second year on average, some children began to speak as early as 10 months while others did not achieve the first word milestone until 18 months.
