7Goldfield, B.A. and J. S. Reznick. 1996. Why does vocabulary spurt? In A. Stringfellow, D. Cahana-Amitay, E. Hughes, and A. Zukowski, eds., Proceedings of the 20th annual Boston University Conference on Language Development. Vol. 1. Somerville, MA: Cascadilla. Pp. 249 -60.
8Gopnik, A. and A. Meltzoff. 1987. The development of categorization in the second year of life and its relation to other cognitive and linguistic developments. Child Development 58,1523-31.
9Gopnik, A. and S. Choi. 1995. Names, relational words and cognitive development in English and Korean Speakers: Nouns are not always learned before verbs. In M. Tomasello and W. Merriman, eds., Beyond Names for Things: Young Children's Acquisition of Verbs. HiUsdale, NJ: Erlbaum. Pp. 63-80.
10Halliday, M. A. K. 1975. Learning How to Mean: Explorations in the Development of Language. London: Edward Arnold.
