"Macaronic" means a text that mixes languages for comedic effect. It's deliberate, pun-based code-switching, in linguistics terms. My students do it, when they hear English that "sounds funny" to them in their Korean ears, and they will suddenly start repeating some random word or phrase that I've said and laughing, no doubt because it sounds like something in Korean that's funny. I can't think of an example at the moment, but I have these moments constantly in my classes.
I ran across a macaronic poem mixing Latin and English while browsing the Language Log blog – a commenter had posted a poem by A.D. Godley entitled "Motor Bus" to an original posting about the syllabuses/syllabi debate. It's a play on the fact that "motor" and "bus" are both words of Latin origin (although truncated and changed) and therefore they might be required to participate in the complex Latin morphology in a multilingual discussion of motor buses.
What is this that roareth thus?
Can it be a Motor Bus?
Yes, the smell and hideous hum
Indicat Motorem Bum!
Implet in the Corn and High
Terror me Motoris Bi:
Bo Motori clamitabo
Ne Motore caedar a Bo—
Dative be or Ablative
So thou only let us live:—
Whither shall thy victims flee?
Spare us, spare us, Motor Be!
Thus I sang; and still anigh
Came in hordes Motores Bi,
Et complebat omne forum
Copia Motorum Borum.
How shall wretches live like us
Cincti Bis Motoribus?
Domine, defende nos
Contra hos Motores Bos!