Additional language

From Teflpedia

An additional language is an individual language that is additional to the other language(s) a person can use. It's sometimes preferred to terms like foreign language (because said language may or may not be foreign and foreignness is hard to define) or second language (because for a polyglot said language may in fact be a third, fourth or even higher). The downside however is that it is not widely used and may not be readily understood. It's sometimes abbreviated by the term L+.

English is often an additional language - see English as an additional language.