Vocabulary growth in late talkers: lexical development from 2;0 to 3;0.

Vocabulary growth from 2;0 to 3;0 was studied in 28 late talkers using expressive vocabulary inventories reported bimonthly on the Language Development Survey (LDS). Group milestones were 18 words at 2;0, 89 words at 2;6, and 195 words at 3;0. A sub-group of 11 children (Group 1) showed a rapid vocabulary spurt between 2;2 and 2;8, reached the 150-180 word mark by 2;6, and attained the LDS ceiling of about 300 words by 2;10. In contrast, the 17 children in Group 2 still had a mean vocabulary of fewer than 30 words at 2;6, had less of a vocabulary spurt when they did start acquiring words, and attained the 150-180 vocabulary mark at 3;0. All 3;0 language outcome measures were significantly predicted by LDS vocabulary size from 2;2 to 2;4.