My two-year-old daughter is way ahead of the curve in her language skills. She had a 150+ word vocabulary at an age when the pediatrician would have been happy with ten, and now regularly strings together fifteen-word sentences with multiple dependent clauses.
One thing we're still working on, however, is the appropriate use of pronouns. She hasn't yet grasped the concept that "I" refers to the speaker and "you" to the addressee, hence statements like "You don't want to take a nap" and "Want me to carry you" (that would be a feat!). So far we've tried just restating things correctly, but maybe we ought to just sit her down and explain how it works. She understands more than we think.