my 23 months old baby has not started talking yet? what should I do

A. Hai good morning !! By 1.5 to 2 years babies start speaking small two letter words, saying mama,papa,dada,hai,bye by waving hands,saying yes,no by nodding,smiling , can understand our commands . Check if baby responding to his/her name,giving eye contact,speaking small words. If any delay then need assessment by developmental paediatrician or speech therapist.