My daughter won't communicate much?I

She has just turned 3 on January 14th. She can say words, recite poems, repeat whatever we say, knows colours, alphabets, objects and many other things. But when it comes to communication she is not so responsive. She won't talk sentences or understand what we say. She can respond to words and she can demand food or bathroom calls or sleep but that is it. I mean she won't make a whole sentence and ask for something very specifically and clearly. But she can point and ask and demand. We are very worried about her. And we are not sure what it is and what to do about it and who to consult. Please tell a desperate couple what they can do about such a problem with such a cute baby. We want her to be best equipped for such a harsh world out there. PS: Her eye coordination and some other things seem to normal. I thank you in advance. Best Regards.