A: I'm so glad you're asking this question now, instead of later. In general, toddlers start to say their first meaningful words around their first birthday. There is certainly a good deal of variation though, as many quiet or shy children tend to speak later. What we really focus on is comprehension -- does your toddler understand what you're trying to say and able to communicate his needs?
Don't worry, but do ask the pediatrician about your son's speech and language development. If there seems to be a delay, your child can receive a free developmental evaluation from your community's "Part C" provider (if you live in the U.S.). I'm a huge fan of Early Intervention services, which helps a child get on track developmentally before the age of 3, and each state has its own. Even if your child doesn't have a delay, the Early Intervention folks are terrific resources and have great ideas for boosting language skills!