My son is 21 months old. He alternates between his grandmas houses during the week. While me and his daddy work. My mom speaks spanish to him so do I and his daddy speaks english to him and his granny on his dads side speaks English to him. My son knows about 10-15 words in each language. I dont want him to get confused? What is the best way to improve his language skills. He usually asks for things with only one word.A friend was telling me he should be using two-3 words sentences.Is this true?