Celie hires two older unmarried women to help her to make the pants that she (Celie) designs. One of the women attempts to teach Celie to speak in proper English, using proper grammar, but Celie says she's too old to learn now, to change the way she speaks and writes.
Celie's response to the woman who wants to teach her proper grammar is significant: Celie feels she has found her voice, found herself. She has spent so much of her life feeling shame for being a woman, for being black. But now that she doesn't she doesn't care about "proper" grammar. She likes who she is; and wants to speak as she speaks, in the voice that is hers.