Every child grow at their own pace. Try to introduce some good nursery rhymes to him. Rhymes are a valuable way to introduce the sounds of a language and practice speaking in a fun and motivational way.
Not only are nursery rhymes a pleasure to hear and to share, they provide a building block toward literacy. By playing with the short texts of rhymes, children explore the mechanics of the language. A rhyme, for young children, is a complete, short experience, which fits well with their limited attention span. It is like a compact story: it has a beginning and an end, and its own content. Once children have worked out these sequences, they feel confident, as they know that the language content is fixed, even if the speed of reciting might alter to match a mood. Here are some links...
Rhymeslyrics.com
Rhymes for kids
Poems for kids
Stories for kids

or you can see them or YouTube in a more interactive way.