In linguistics, first language acquisition is closely related to the concept of a "native speaker". According to a view widely held by linguists, a native speaker of a given language has in some respects a level of skill which a second (or subsequent) language learner cannot easily accomplish. Consequently, descriptive empirical studies of languages are usually carried out using only native speakers. This view is, however, slightly problematic, particularly as many non-native speakers demonstrably not only successfully engage with and in their non-native language societies, but in fact may become culturally and even linguistically important contributors (as, for example, writers, politicians, media personalities and performing artists) in their non-native language. In recent years, linguistic research has focused attention on the use of widely known world languages, such as English, as a lingua franca or a shared common language of professional and commercial communities. In lingua franca situations, most speakers of the common language are functionally multilingual.