Developmental norms for young children's vocabularies have a number of
applications in research design, assessment, and intervention, but ha
ve previously been very difficult to obtain. In the present study, mon
th-by-month norms for comprehension and production of 396 words from 8
to 16 months, and production of 680 words from 16 to 30 months, were
derived from a norming study of 1,789 children between the ages of 8 a
nd 30 months using the MacArthur Communicative Development Inventories
(Fenson et al., 1993). The norms are available in the form of a datab
ase program, LEX, for MS-DOS-based computers.