Perisylvian polymicrogyria

Perisylvian = surrounding the sylvian.

Polymicrogyria = an anomaly of cortical development in which neurons reach the cortex but are abnormally distributed, resulting in the formation of multiple small gyri.

Source (of definition):
Rocha de Vasconcelos Hage, S. (2006). Specific Language Impairment. Linguistic and neurobiological aspects. Arq Neuropsyquiatr.