Definition of "basilectal"

I prepared the three Matched Guise samples myself, controlling the forms carefully to represent basilectal, mesolectal, and acrolectal levels of usage.

1985, Nessa Wolfson, Joan Manes, Language of Inequality, page 158

It is tremendously important to study basilectal speech, but this valorization process has had some unfortunate byproducts.

1996, James E. Alatis, Georgetown University Round Table on Languages and Linguistics

While the use of basilectal French in colonial novels serves principally to depict the linguistic realities of interaction between colonial rulers and their subjects during the colonial era, the inclusion of basilectal French in novels set in the post-independence era generally functions to provide information on the social or educational status of a character.

2014, Kathryn Batchelor, Decolonizing Translation