Here are some websites parents can use to find ideas on how to supplement speech therapy and encourage language development at home.
Playing With Words 365: Lots of concrete tips and tricks to help your child with the building blocks of language. Check out the What Type of Communicator Is Your Child? post to determine your child's communication style.
Favorite Songs and Finger Plays: Some kids respond best to language when it's presented in song form. Adding gestures helps to hold kids' attention and allows children who aren't ready to talk to participate in the song.
10 Non-Tech Gift Ideas to Promote Language, Learning: Nice list of toys to provide language opportunities for kids.
How to Talk to Your Child's Doctor: A handout from the Center for Disease Control about addressing your concerns for your child.