Thing is, reasonable languages adapt loan words to their own rules to make their speakers’ lives easier.

English, though? Nah, English just stalks other languages in dark alleys, stabs them, rips some random words off, and runs away giggling like a maniac, bits of the original language dragging behind, leaving a trail of gore.

That’s how you end up with things like façade, or naïve, or fiancé, or the plural of radius being radii, or château / châteaux, or referendum / referenda, and so on, turning what should be a matter of just applying some standard rules into a veritable minefield of non-standard forms which must be memorised by its speakers.