'English-language' originates from Modern English as a compound of 'English' and 'language', where 'English' refers to the people/language of the Angles and 'language' refers to a system of speech.

'English' comes from Old English 'Englisc' (from the Angles, 'Engle'), and 'language' comes from Old French 'langage' (from Latin 'lingua' meaning 'tongue'); these elements combined in Modern English to form the compound 'English-language'.

Initially the elements referred separately to the Angles/people ('English') and 'tongue' or speech ('language'), and over time the compound came to be used to denote things 'in or relating to the English language' as a modifier; the core sense of referring to the English tongue has been retained.