Figure 4.

Illustration of hypothetical distinction between different kinds of typical and atypical language lateralization. Red and purple regions correspond to different language functions (e.g. naming and series repetition as tested in the Wada test). The typical developmental progression is from more diffuse language representation in infancy that steadily becomes more focal as skill develops and synaptic pruning occurs. Usually both language functions will be represented in the left hemisphere, but normal language function is compatible with separation into left and right hemispheres. For children with language impairments, the developmental progression to focal representation is much slower if it occurs at all.