There is conflicting research on the optimal age for learning Spanish and other languages. Some research suggests that children can acquire a second language easily up to the age of 10. Other research refutes this view. Children who live in family with two different language groups often learn to speak both languages fluently. However, this does not mean that they have acquired all the necessary communication skills in that language. Learning conversational Spanish, for example, does not mean that the child will be fluent in formal or written Spanish. Some research suggests that children find it harder to acquire a second language after the age of five. Recent research suggests learning a foreign language while young helps the brain to develop. This is a great advantage for children who are learning Spanish.