You could probably get a few more bits of entropy kind of easily if you use words from other languages. This doesn't help the monolingual among us but it's great for me.
(Actually, slightly less since some words exist in both languages. Like `hell'.)
Well, sure -- but once you're at around two or three languages, you get to imagine that the attacker doesn't know what languages you're using. If I use English, Japanese, and Spanish, I can figure on the attacker needing to check the Germanic (English, Dutch, German), Romance (Spanish, French, Italian), and Asian (Japanese, Chinese, Korean) languages at a minimum.
Jargon helps too, and proper names. "dijkstra bicycle entonces boojum daihinmin"
Instead of that, just add an extra common word: "correct horse battery staple bicycle".