Learning that classifiers count: Mandarin-speaking children's acquisition of sortal and mensural classifiers.

Two experiments explored two-to five-year-old Mandarin-speaking children's acquisition of classifiers, mandatory morphemes for expressing quantities in many Asian languages. Classifiers are similar to measure words in English (e.g., a piece of apple; a cup of apples), with the main difference being that classifiers are also required when counting sortals (e.g., yi ge pinguo or "one unit apple" in Mandarin means "one apple"). The current study extended prior studies (e.g., Chien et al., J East Asian Linguist 12:91-120, 2003) to examine Mandarin-speaking children's understanding of classifiers as indicating units of quantification. Children were also tested on their knowledge of numerals to assess the relationship between children's acquisition of numerals and classifiers. The findings suggest that children first notice that sortal classifiers specify properties such as shape. Only after learning some numerals do they begin to work out how classifiers indicate units of quantification. By age four, children scored above chance on most classifiers tested.