Knowing which form of words to use

[Suzune]

i feel really disheartened by the number of exceptions. I have a hard time understand whether you just have to memorize everything or whether there is a system. For example sometimes the mouth kanji uses guchi and sometimes it uses kuchi with little rhyme or reason for why that is. Or in marble you use dama rather then tama. Why would this be. I am not sure if it is the equivalent of saying does that sound right, but I feel quite flustered by the constant changing and I am looking for some kind of pattern to help me know.

[ChrisDalton]

Sounds like what you’re talking about is rendaku, when a syllable changes to its voiced counterpart. Here’s a (pretty in depth) Tofugu article on the topic: Rendaku: Why Hito-Bito isn't Hito-Hito

For now, and I know this isn’t great to hear, but I’d just try to memorize them. Make sure you really check the pneumonics mnemonics, sometimes they’ll have a way to remember when it changes. Although admittedly most of the time it’s just “remember that there’s rendaku lol”

This may sound weird (and maybe it’s just my imagination) but it seems like you kinda get the hang of it after a while. During new vocab lessons I find that about half the time I can tell that there’s a rendaku just from trying to sound it out in my head, where a certain syllable just doesn’t feel ‘right’ without the change. I promise it won’t be a huge issue as you progress, the real challenge is when you have a couple hundred reviews queued up, but you won’t have to deal with that for a while (and when you do you’ll be totally ready with all your butt-kicking kanji knowledge).

[aeolianaether]

Rendaku does follow rules, but they’re very complicated so it’s easier to just memorise each individual situation. Eventually they will just sound right.

[Belthazar]

Aye, “you’ll get the hang of it over time” is my advice.

Compare with the English letter C, for example - sometimes it makes a S sound and sometimes it makes a K sound, but how do you remember which is which? Well, you don’t really - you just remember that, say, “compare” has a K sound, “sincere” has an S sound, and “circle” has both. You’re not constantly thinking which sound is which, you’re just learning the words.

[alo]

Around Level 5 is when started to guess a lot more correctly on the pronunciation of a word. That’s when you start to learn enough words to figure out a rough pattern.