There's not necessarily a correlation between walking and talking, but it is very common for different children to meet milestones at different rates and in different orders. Some things are easier than others, and that differs from person to person, even as adults. Sometimes it's not a matter of competence, but of personality. Some people just plain like to listen more than talk, even as adults.
Especially you can't compare milestones between children with different parents. I know some parents who literally spend hours a day working on getting their babies to talk. Other parents are so good at anticipating needs that their babies don't have much need to talk. I'm not terribly surprised when the first baby learns to talk faster, although even then there's no guarantee.