Let's talk talking

My 18 month old is my 2nd born.

Our first has a speech delay, we knew pretty early that it was a possibility because he rarely talked!! Anyways, he's in therapy and doing so much better.

But now with our baby, I'm worried he might have a speech delay as well. He babbles and is saying word and that's more than his brother ever did!!! But he doesn't talk all the time, and he says only a handful of words. He also doesn't say them all the time. We go to his check up next week so I'll obviously being asking about it then.

But I'm just so worried because I feel like soany others are talking so much. And it makes me feel like a failure or like I'm doing something wrong if it is happening all over again. But yet I'm literally doing everything I've learned from my sons therapy teacher, I read to them seriously daily, and I just feel like it's not there. Or maybe I don't even know what's normal and what's not since my first was delayed. Idk!!