FTM.

I’m a little worried about my son. He is 1 year and 8 months old. He can say mom, dad, pa, ma etc and he knows and follows me whenever I say the alphabet and numbers 1 to 10. He really loves trucks, buses, trains etc. He understands when I tell him to throw his dirty diaper in the bin and can follow other instructions. He can eats by himself and lets me know when he pooped and pee. However, I'm concerned because when I call his name, he often doesn’t respond and he rarely looks at me. He does recognize parts of his name, for example when I say "DA," he can say "NIEL." Is this normal, or should I be worried and take him to see a doctor?