interlanguage

[ in-ter-lang-gwij ]
/ ˈɪn tərˌlæŋ gwɪdʒ /

noun

a language created or used for international communication.
(in second-language acquisition) the linguistic system characterizing the output of a nonnative speaker at any stage prior to full acquisition of the target language.

Origin of interlanguage

First recorded in 1925–30; inter- + language