Anyone’s 17month old not talking?

NNEJ • 35 Yr old Mother of 2 girls and 2 boys 🥰💕💙

My son has yet to form any words and I’m getting a little concerned. He knows what everything is and will hum along to songs and understand what’s what but he hasn’t tried to say any words besides his sisters nick name which is “Mima” and he says “mma!”