she is not lazy. generally children who speak late are not lazy. I hate that late talkers are qualified as lazy, it's rubbish.
People shouldn't assume that a child has a speech delay because parents don't speak to them or converse enough with them. That's really not it at all, it's a comment usually made by people who either have children who don't have a speech delay or worst, by people who don't have children. Or by mothers in law.
Speech development is a very complex process and some children develop it slower and later than others. It takes more efforts. The first thing to do is to have her ears checked, so you can get a referal by GP or HV. Go on the waiting list for salt as in our area it took 3 months to get initial assessment.
I have a 3.4 DS and he was very late at developing his speech. He has been assessed top to bottom and he is spot on with all areas of his development. We speak to him all the time, he has a beautiful relationship with his older brother who has no speech delay.
I found that proper words were not the first thing he said, neither were nursery rhymes. But sounds, car sounds, things like oh oh, plane sounds, animal sounds, and unique sounds (for example, he know most letter phonics months before he could speak - he could say SSSSS but not Sit) and he couldn't put sounds into meaningful words.
He has now started t alking but he is about 18 months behind, and nobody in the professional sector - salts, psychologists, neurologists, pedeatricians EVER told me that my son wasn't talking because he was lazy or because we were not talking to him enough.
There are some very well recognised methods that we have used to encourage his speech, especially the book It Takes Two to Talk.
Please please don't listen to people who say that she is lazy or that you don't speak to her enough.