A child's first words are magical. Whether it's "mama," "dada," or something else entirely, you feel a mixture or love, pride, and amazement at how quickly your baby is growing. Unfortunately, the process of learning to talk can also be a source of stress for parents who worry their child is falling behind developmentally. Although a baby or toddler's vocabulary is relatively small, it should be expanding rapidly by age 3. In fact, there are some words your kids should be saying before 3 years old that you'll want to listen for to make sure they're on track.