Macaronic Lyrics
From HymnWiki
Macaronic lyrics are song texts which switch back and forth between two or more languages without missing a beat. The most common occurrence of lyrical macaroni is in medieval European Christmas songs such as In Dulci Jubilo and the Queen's College Boar's Head Carol, which switch back and forth between Latin and a vernacular tongue (in these cases, originally, German and English respectively).
