I was wondering why is Wanikani doing this:
とおす: many words are written like this, the long vowels are somewhat arbitrarily written this way, instead of like this: とうす. An お instead of an う. Why?
Because for example this one いもうと is written with an う, as I would expect.
And the pronunciation is the same as いもおと, but it’s not written like that.
I don’t’ really know when which word constitutes which. Help!