Speech delay and suspected down syndrome

Hello doctors, My daughter is 2.9 yrs and she is very active and has always covered her developmental milestones more or less within the time frame. But all she has problem is of a delayed speech she uses just one words or gestures to get her requirements fulfilled,she does not join words and even if she speaks it is not clear. One thing to note here is that if anyone reads out the alphabets aloud she repeats after that and she speak only few words on her own , ONLY THOSE FEW WORDS ARE CLEAR. so i was really upset and decided to get some medical help this is where i visited a homeopathic practitioner and he told me that she is MOST PROBABLY having a down syndrome just by looking at her facial feature- slanted eyes, flat face etc. Let me mention here that her father is from a tribal community so my daughter's facial features somewhat looks like my husband. The doctor even told me that he is not sure of it 100% but chances are there. please tell me where to get it diagnosed and treated?