My 14 month old boy doesn't babble much and only says baba, papa and kaka. He doesn't ever say mama and doesn't refer to anything or anyone by name. He does understand when we say certain words like mom, dad, milk and water. He also doesn't clap, wave or point to anything and doesn't imitate us much. The only times he imitate us is when we cough or when we say kakakaka.
He is otherwise a happy baby and walks well. He also eats and sleeps reasonably well. We are a multilingual home and he is exposed to 3 languages. Should I be worried? Does this signify a speech delay?