Children's Acquisition of the English Cardinal Number Words: A Special Case of Vocabulary Development

When children produce the names of the cardinal numbers from 1 to 1,000,000,000,000 in English, it is unlikely that they have previously learned all of these words. Rather, children have probably learned a small set of basic number words and by combining these elements, construct additional words. To understand the development of number-word construction, students in Grades 1, 3, 5, and 7 named and counted from a set of numbers into the billions in 2 studies. Times taken to produce numbers were also recorded in Study 2. Despite large individual differences within grade, number knowledge increased dramatically with age, and many students in Grades 1, 3, 5, and 7 produced number words in the hundreds, thousands, millions, and billions, respectively. In Study 2, times to name and count decreased substantially with grade. The findings are discussed both in relation to children's growing knowledge of the number system and to vocabulary development.