Late talkers (LTs) — children who show a marked delay in vocabulary learning — have also been shown to differ from normally-developing (ND) children with respect to the semantic organization of their learned vocabulary. We use a computational model of word learning to study how individual differences between LTs and NDs give rise to differences in abstract knowledge of categories emerging from learned words, and how this affects their subsequent word learning. Our results suggest that the vocabulary composition of LTs and NDs differ at least partially due to a deficit in the attentional abilities of LTs, which also results in the learning of weaker abstract knowledge of semantic categories of words.