I also heard it’s boys that as a whole acquire their mobility skills sooner, and girls that talk sooner. I think it’s probably an individual thing. I did notice with Sarah that she was a slow crawler, slow walker, and an early talker. Hailey was on the slow side with everything, but once we got her hearing issue sorted out, her speech took off.
Enjoy the walking! It’s so much fun when they start walking around. Somehow they start to seem like real people.