So kyntons about to be 18 months and he had went thru a phase of trying to say new words. But these past few months he…

So kyntons about to be 18 months and he had went thru a phase of trying to say new words. But these past few months he won't try. He just does the baby babble. I almost feel like he is falling behind. He refuses to try. He only says Daddy and Hersh (our cats name is Hershey). He says Nana for food and juice. Which we got him into saying Nana for when he wanted bananas but now associates all food that way. Is it normal for him going on 18 months and not even trying to talk. Even small simple words. He just doesn't try. The closest he has came is when I slowly say I love you, he makes sure to baby babble back 3 words but that's it. Maybe it's just him being stubborn but is there something I can do to try and get him into wanting to say and learn words or do I just wait?