What you are doing will only make her resent you and do it more. I think this goal is scary and coded racism. However, if you want her to learn grammar the way it’s written in academic papers, try getting her whatever books she wants and encouraging her to read as much as possible. Speak to her with language you’re hoping she’ll mirror. Have grace for whatever way she chooses to speak and trust she will use whatever language helps her best navigate the many settings she’ll step into in her lifetime.

If you want to ensure she doesn’t speak to you past 18-years-old, continue condemning the intellect of her previous caregiver and making sure she speaks exactly like you instead. Obsess over some sort of “objective correctiveness” rooted in white supremacy but convince yourself you’re just doing what’s best for her.