I don't see English to be considered as official language for a country. We have different cultural background, different economy, and different norms and what the society values differs from one another. Taken English as the official language of a country like Nigeria is posing a lot of damage to the cultural heritage. Most local languages is been replaced with English. The best way to teach a child is the use of the indigenous language. You can't expect an English man to refuse to speak English and taken Yoruba language as a means of communication. Although, It has it's own advantage because it's widely spoken across the country. The disadvantages using English is that most country that don't speak the language becomes more or less irrelevant and the need for interpreters is required. I will recommend It as the second language to be spoken in countries that have there local language. Thanks.