The aim of this study is to analyze vocabulary development in "late talkers". Subjects were selected from a wider sample of 42 infants, longitudinally observed during the second years of life, by identifying all children that, at 24 months, were under the 10° percentile as regards normative data for Italian population. These infants have been compared, at different stages of their lexical development, with a control group balanced for sex and birth order. The most important results concern: a) the possibility to identify infants at risk even since 18 months of age; b) the substantial homogeneity of both "late talkers" and "normal infants" with regard to language comprehension and symbolic gestures production; c) the lexical development recovery style and nature displayed by some "late talkers" during the third year of life. Results are discussed in the light of different models concerning delayed language development explanation.