Years ago I used Dr. James McDonald's(father of an autistic child) speech resources online(no longer free), and I learned quite a bit about how to go about helping my late talker with at-home speech therapy. I noticed recently that he published a book, Play To Talk: A Practical Guide to Help Your Late-Talking Child Join the Conversation It has gotten very good reviews.
Play to Talk is a hot new parenting resource you won't want to miss! This award winning book has been recognized by iParenting Media Awards as a 2008 Best Product, and is a Gold Award winner in the 2008 National Parenting Publications (NAPPA) Parenting Resources competition. Based on 30 years of clinical research, Play To Talk empowers parents with proven strategies and step-by-step instructions to help children of any age learn to talk and develop essential skills for conversational relationships and social interactions. Guided by the belief that families have the greatest influence on a child's social and communicative development, Play To Talk will help you create closer and more fruitful relationships with the children in your life. This approach turns everyday play sessions and social interactions between your child and family members into opportunities to foster language development, relationship skills and positive behavior - without taking the fun out of being together.
Also helpful are these naturalistic speech therapies(free) from Dr. Camarata(father of a late talker) of the Vanderbilt Brain Institute. I used these at home with my son(eight years ago) and presently with my late talking preschool daughter.