my son is 2yrs 11 month he is not speaking at all what is the problem I am not understanding

A. Hello good evening !! If baby is not speaking small words,not recognising,not responding to speech, commands then need to concern.. Check if baby is active , giving direct eye contact or not. Consult developmental paediatrician for assessment. By 1.5-2 years babies start speaking words, responding to commands , recognising things so for assessment with developmental pediatrician or speech therapist.