What makes comprehensible input comprehensible?

> Word length - At least in English and French (the languages I know best), longer words are generally considered harder.

I think in a language with a lot of similar sounds or even homophones, longer words are easier. For a beginner Chinese speaker that knows both words, hearing "chē" will probably be ambiguous, but "chūzūchē" will be parsed immediately.

That’s a good point.

I don’t think the ‘longer equals harder’ pattern holds for every language. I actually reached out to the head teacher at CIJ when I first made this analysis and she said the same.

This is mainly resolved by context. "Penultimate" is a harder word than "pen". Now that could also mean "penitentiary" in North American vernacular, or a box in which a pig is kept, but not in a sentence like "Can I borrow your pen?"