Never seen this. Do you have any examples or a source?
Yeah, this isn't something I've ever heard of.
From https://pomax.github.io/nrGrammar/#section-3-2-7-1-Dubitative_/_cohortative :
The way in which the direct pseudo-future is constructed differs for the two verb classes: 五段 verbs get う added to the 未然形, but the combination of the 未然形 あ—row syllable and the う changes the pronunciation (as well as written form) to an お—row syllable instead, so か+う becomes こう, ま+う becomes もう, etc. To see why this happens we have to look back at classical Japanese, where the combination of an あ—row syllable and an う always changed the pronunciation to that of the corresponding お—row syllable; not just for 未然形 constructions, but for any written combination of the two. While the language reforms of the mid 20th century changed many of the rules for written language so that it would correspond to spoken language more, constructions involving the 未然形 have generally been left alone (another 未然形 'quirk' can be found in 五段 verbs ending on う, which becomes わ rather than あ).
Hi lake, I don't see how the conjugation rules for the "direct pseudo-future" are related to the OP. To be honest I also don't understand how the OP is related to the word 違う, as there's no あう or おう inside it anyway.
Thanks, Lake actually answered my question.
Sorry I wasn't more clear, but I was talking about the sound of a kanji with an あ sound, or row syllable, rather than an actual あ character/kana
Hi there, I think I know what might be talking about, but it pertains to historical linguistics, and it's not something you really need to know when learning Japanese. Anyway:
Kanji that had an あう sound in the Kamakura period (not sure of the exact period ?) changed to an おう sound in modern times. Some examples:
奥 おう was originally pronounced あう
皇 おう or こう was わう or くゎう (kwau)
広 こう was かう
島 とう was たう
If you look in a Japanese dictionary, next to the part where they tell you the reading, there is often another reading in brackets indicating the historical reading. Here's the entry for 皇 if you want to take a look. https://kotobank.jp/word/%E7%9A%87-448702
Now here's the interesting part. Up until 1946, even though the pronunciation had changed to be like it is today, people still wrote in the historical way (pronouncing おう while writing あう). This is kinda like how English speakers write 'knife' even though no one pronounces the 'k' anymore. Then in 1946 the government reformed the kana spelling to how we write today. So if you look at a piece of writing from WWII and earlier, the kana spelling is going to be quite different. Here's an old poster I googled: you can see that 買いましょう is written as 買ひませう. https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ-DGUvboH4fyFecZUpR5ptKHXbjqFqNcvKMMsFc-enj2ir39fu&s
As an aside, 違う was originally ちがふ, so it does not follow the あう to おう rule.
あ+う=おう
I picked up somewhere that あ+う=おう was true
But I guess that's not the case
or maybe it's a rule of thumb with some exceptions ?
Or does this rule only apply when to separate words, with those letters, are combined in a sentence, not to words themselves, mayhaps?
Or is it completely baseless?
Any feedback would be much appreciated : )