Is there a method or pattern, or perhaps a word that explains what this concept is? What I mean to say is… 口 has a kun’yomi reading of くち and when I first learned 川口 … I expected it to read as かわくち . So what is this rule, or concept that is happening here? Why is it pronounced かわぐち？ Do many words do this? Or only some? Is there a rule you can follow to know when this happens? Or do you simply have to memorize it?
I don´t know if that -always- happens, but I see that everywhere. “達” for example… The kun reading is -たち, but in the word 友達 the た is replaced with a だ —> ともだち
Yes, this happens a lot. To put it in slightly technical terms, the first consonant becomes voiced (meaning that the vocal cords vibrate). Consonants come in voiceless/voiced pairs, for example t/d p/b s/z k/g f/v and so on. So kuchi become guchi and tachi becomes dachi when the kanji is being pronounced after another kanji. But this doesn’t happen all the time, so you kind of just have to memorize it.
I was thinking it was something along those lines. Isn’t there a linguistic term for this, too?
Ah, I found a term for this happening in Japanese. It’s called rendaku. 連濁 - “sequential voicing”
I didn’t know it was called rendaku 連濁 in Japanese. And I didn’t know the rule of it.
However, I can say rendaku words properly and naturally as a Japanese native.