Anybody who can help this poor kid?

The above picture is of a child who needs special intervention as she is kind of mute as her mother is deaf-mute (deaf and cannot speak). This child is not a typical deaf-mute like her mom who, on the other hand, is a deaf-mute since birth. Her story is little different and I don't know the name of this medical condition (or diagnosis). The interesting thing is that her older sister does not live with her mom (she is away living with her maternal uncle) and because of that she can speak clearly but this unfortunate girl does not know how to speak words. She has seen her mother communicating with others with the help of sign language and she being very close to her mom from birth could not acquire the skills to speak words like her older sis. This is partly because she tries to imitate her mom when she needs to communicate and she thinks that it is the natural way. I saw this happy and jolly girl when I visited India (she is actually our neighbor and belongs to a poor family) and felt utterly bad for her. She plays with other kids normally and mingles with everyone but she cannot communicate with words: all she can do is just make some sound to imitate words that she wants to express. I am sure with medical intervention (like speech therapy) she will be able to speak because she is not a born deaf-mute like her mom which is evident from the fact that she can listen to what others are saying and tries to reply accordingly. Unfortunately, nobody seems to care about her problem (which is kind of common in rural India) and she is being denied this wonderful gift of language. Anybody out there knows about this condition and the treatment options? Any help will be highly appreciated.