Talk to Pediatrician on Speaking Words

My son is 21 months old. MashAllah he is active and healthy. The only problem is that he hasnt started speaking words yet. He says mama, baba, dada, dood (milk), tata and maybe 1 or 2 other similar words. When we try to teach him to speak some word, he just dont say. Sometimes he try to listen and watch lips movements, but most of the time he just dont want to focus, but play.

He understands every words. If we ask him to do something he does it neatly. He points at things he want. He talks in his language a lot. He also remember the music of some poems and make sound that kinda resemble that music.

He is our first and only child. We live in a joint family so often plays with his cousins