are you saying it's because a daily doubling is itself exponential
Yup, that's what I'm saying! I'm not the kind of person who will get on someone's case for using exponential colloquially to mean "growing really fast", but when you explicitly describe an exponential function and then imply that it's not exponential, that's just sloppy. Bringing in nonlinearity, which makes it seem like you're being more mathematically formal, makes it even less acceptable.













This is also a case of having different needs from an immersion text: I've now gotten to a point where I actually want something on around a high school reading level without furigana (or without copious furigana, at the very least) so I can really test and reinforce my kanji and vocabulary knowledge. But early on, I was much happier to read something along the lines of Yotsuba&! which I could get through without giving up in disgust. It's all about finding that right balance of challenge and enjoyment.