Yes, boys typically start talking later than girls.
And yes, twins often start talking later than singletons.
These facts dampen my worries that these 21 month olds aren't talking much yet. But this knowledge fails to lessen my extremely strong desire to communicate with them using words. I mean, obviously I talk with them (all the time, in hopes that this will help) - but I hear very little response through words. They understand exactly what I'm saying and they easily follow 2-part directions. There's no problem with their comprehension. But they don't use words to tell me what's going on inside those cute little heads. And I'm dying to know. I yearn for that kind of relationship and it feels like I've been waiting forever. "Luv you, momma" is something I know will melt my heart and I just wish it would happen sooner than later. Instead, J and I express glee about the one word they both have started saying - "No". Actually, it's really funny - G was very tired last evening, because he refused to take a nap after playtime at the park and he was kind of whiny. I told him, "I understand, you're tired", and he responded NOOOOO. It's like, he understood not only what I was saying, but what I was implying (it would be bedtime soon). Just these little glimpses of what 2-way communication can be like with them just whets my appetite and leaves me wanting more.
They're certainly working on their large motor & fine motor skills in lieu of the verbal skills, though! They both can thread Cheerios onto dry spaghetti noodles stuck in play-doh. W can climb up the "big kids" playground equipment at the park and hang from a bar. Both boys can throw the ball overhand, they're both running, and G is jumping. W is trying to figure out how to throw things straight up into the air, since watching me demonstrate. It's fascinating to watch them learn new things and it's so fun to see how proud of themselves they are. So, I try to take great joy with their accomplishments rather than focusing on what we don't have (yet).