What to do if toddler 2 y/o still cant talk or understands you

My daughter is two years old now. She is in playgroup class . I assume all of her friends has started talking to each other but my daughter is introvert and nvr talk anyone in school. She is only giving hand gesture when she in needs or wants something. I am not sure what to do and I know its speech delay. Its my fault for giving her screentime before she turns one year old. I'm trying not to give her screentime anymore but despite staying with grandparents, they gave her watch screentime behind us, without us knowing sometimes. She is improve alot when she is not watching screentime. But is there other ways to help out what to do if my daughter speech delay?