Frankly, I don't think you understand Japanese morphology at all and are blowing a whole load of hot air. The inflection of arigatashi -> arigatou is quite str

Frankly, I don't think you understand Japanese morphology at all and are blowing a whole load of hot air. The inflection of arigatashi -> arigatou is quite straightforward and any adjective in Japanese can undergo the same inflection: - arigatashi -> arigatai: modernization - arigatai -> arigataku: adverbalization - arigataku -> arigatau -> arigatou: u-onbin It would perhaps also help your case if you didn't misspell "arigatou" twice in your post, either.