Curious Kids: are some languages more difficult than others?

Some languages seem harder than others. Does that mean that the brains of people who speak those languages are more stimulated? – Maria Júlia, aged 14, São Lourenço, Brazil

Are some languages harder than others? For example, is Japanese more difficult than English?

To answer the question, the first thing we have to do is distinguish between babies learning their first language and children or adults learning a second language. For babies who learn their first language, no language is harder than another.