At the global level, many children learn language in bilingual or multilingual environments. They may hear and use one language at home and another at school and in the community. Some children learn more than one language in their home if the family uses more than one language in every day interactions. There is significant variability with respect to what language(s) children learn, when they learn each language, and in what context(s) each language is used. Children may hear and use different languages in the home, school and community. Developmental language disorder (DLD) affects approximately 10 per cent of the child population, including children with exposure to more than one language. A diagnosis of DLD in multilingual children should consider all languages a child hears and uses. Language learning is difficult for children with DLD and manifests across all their languages. Bilingual and multilingual children typically use forms that show the mutual influence of their languages. These influences are not indicators of DLD. Despite having difficulty with language learning, bilingual and multilingual children are not more likely to have DLD (though they may be at risk for misdiagnosis). Language intervention approaches for multilingual children with DLD should involve all their languages.