köken: Originally a compound of 御 (o-, honorific prefix) + 早く (hayaku, “early”, adverb), from adjective 早い (hayai, “early”). Modern Japanese -i adjectives formerly ended in -ki for the attributive form. This medial /k/ dropped out during the Muromachi period, both for the attributive form (-ki becoming -i) and for the adverbial form (-ku becoming -u). However, the adverbial form reverted back to -ku…
köken: Literally, “good day”. The original, now dated, form was dobry dzień (which see for more), which at some point began to be pronounced as dobrydzień (now dated and dialectal) with the stress on -bry-; to prevent the spread of that rural form, the words were rearranged.