I think there was a tradition of German-Latin macaronic carols. In addition to "In Dulce Jubilo" mentioned earlier in this thread, I remember from high school
Psallite unigenito Christo Dei filio Redemptori Domino Puerulo jacenti In praesepio.
Ein kleines Kindelein Liegt in dem Krippelein. Alle liebe Engelein Dienen dem Kindelein Und singen Ihm fein.
Psallite, etc.
(You will pardon me if I have gotten some of the endings wrong.)
The following English--dog-Latin one, which I remember from college, is probably 18th- or 19th-century British:
Amo, amas, I love a lass As a cedar tall and sleder. Sweet cowslip's grace is her nominative case, And she's of the feminine gender.
Rorum corum sunt divorum, Harum scarum divo, Tagrag merryderry periwig and hatband, Hic hoc horum genitivo.
Can I decline a nymph divine? Her voice as a flute is dulcis. [line forgotten] And soft, when I tacto, her pulse is.
Rorum corum, etc.
O how bella my puella! I'll kiss secula seculorum. If I've luck, sir, she's my uxor. O dies benedictorum!