I’m having bit of a trouble with figuring out how to instinctively read some of the vocab in terms of which Kun reading I use and when. Is there a rule of thumb for this?
An example is with 入
入れる is read as いれる but 入る is read as はいる
I also notice that 入る can be read as いる to produce a (albeit slightly) different meaning, so how would I know where it would be はい or just い when used in different compounds?
Is this something I’m just going to have to learn for each word or is there a hidden rule?
The most common ones you’ll encounter are probably 立入 (たちいり entering a place), used in 立入禁止 (たちいりきんし do not enter) and 気に入る (きにいる to be pleased with), both of which are taught on WK as their own vocab words.
It will get better later on later levels. One reason for the confusion and lots of possibilities is that you learn the simplest, most versatile kanji in the beginning, which probably already had lots of Japanese words for them before the kanji were imported. This means that more different sounds relate to the kanji.
Numbers are problematic, and stuff like 人女子, body parts 口目, etc.
Sometimes it even matters when a word was imported for ON’yomi. 人 is an example of this. In addition to several KUN’yomi, you have to actively remember if it was じん or にん this time (versions of ON’yomi from different times).
You’ll just have to memorize this stuff in the beginning. In other languages the most basic stuff is the most irregular as well (like to be in English).
The good part is, you can often find patterns that tell you what reading to use.
A good example is 月. When it’s used to describe months, it uses the がつ reading for specific months (including 何月, since you’re asking about a particular month), and げつ for non-specific months (last month, next month, and similar)