Demonstrating language for children who are not yet talking or who are just beginning to talk is most effective if adults use very few words and even easier if they use language that catches and holds a child's interest. Limiting your language use to talking about things that are right in front of you and your child is also important. Some ways of communicating involve using language that has a set melody and calling is a good example of this. When you call, you call with a little song. I have found that any kind of communication that involves a set little melody attracts the attention of children with autism. These kids (all of us, really) find it easier to remember language that has a melody. Here is a little video model of calling and looking which demonstrate what I mean here. Listen to the melody of calling and note how easy it would be for a child to understand what is being said here.