Specific language impairments are characterized by a strong semiological heterogeneity. Numerous classifications have been used to bring out this heterogeneity and to create subgroups after outlining specific symptoms and deficits. However, semiological fixed profiles would not be adequate for these disorders related to neurodevelopmental trajectories. This heterogeneity is not only semiological: it is also found within underlying mechanisms, as well as in the etiopathogenesis, which is still not well understood today. The aim of this article is to introduce the main semiological classifications to highlight the fact that the symptomatic level alone is not sufficient to characterize specific language impairments.