Language is a system of conventional spoken, manual, or written symbols by means of which human beings, as members of a social group and participants in its culture, express themselves. The functions of language include communication, the expression of identity, play, imaginative expression, and emotional release.
Typically, people acquire a single language initially, their "first language" or "native language", the language used by those with whom, or by whom, they are brought up from infancy. Subsequent "second languages" are learned to different degrees of competence under various conditions. An "official language" is a language given a special legal status in a particular jurisdiction. There may be several official languages in a jurisdiction and some may be spoken only by minorities.
Languages have often functioned as an important marker of membership in particular groups, such as ethnicities/races, especially as it is often difficult for adults to learn to speak other, non-native languages without an accent. However, second-generation and later generation immigrants may become fluent native speaker. A conquering group racially different from those conquered may cause the conquered to use the language of the conquerors or the conquerors may start to use the language of those conquered, again making language an uncertain racial marker.