A friend of mine linked me to a comment on reddit which has a great take on the workings of on’yomi and kun’yomi, and how Japanese is based so heavily on meanings.
Imagine a world in which the word “financial” were spelled “$ial”, “monetary” were spelled “$ary”, and “money” were spelled “$”. So we’ve done two things here: we’ve mixed symbols and letters, and the symbols have different pronunciations depending on what word they’re in.
Japanese is like that, except with a ton more symbols, and by the way there are no spaces between words.
Another analogy: imagine if we had a symbol for water (I’ll steal from Chinese and say 水). Now you know how we have all these Greek and Latin roots? Let’s just use the same symbol for those, so we’ll write “hydrate” like “水ate” and “aquatic” like “水ic”. And “water” is spelled “水”.
Japanese is actually a bit simpler than English here. In this hypothetical system for English, each character will get three classes of pronunciations: one for the Latin root, one for the Greek root, and one for the English word. This is because English steals from two foreign languages (Latin and Greek) to get its fancy roots. However, Japanese only steals from one language (Chinese) to get its fancy roots. So each character only gets two classes of pronunciations: Chinese and Japanese.
Final analogy: how do you pronounce 1cycle, 1rail, 1st, and 1?
This could be a help to newcomers how struggle with the “why does is it sui one time and mizu the other??” concept.

