Children can acquire a second language from an early age through exposure in their environment. While some think young children pick up a second language easily, it is actually a complex process that takes many years. Children who learn two languages simultaneously follow the same developmental pattern as monolingual children, and being bilingual does not cause any delays or negative effects. Children who learn a second language after age 3 follow a different progression, as they already have the basics of their first language. Code switching and language mixing are normal parts of second language acquisition as children's vocabularies develop. The goal is improving communication, not enforcing strict language rules.