A company email was sent out with the line "...wykorzystującej na codzień język angielski." The comment has been returned that "... na co dzień..." should be written separated. I'm trying to use google to find out which one is right. Can anyone explain the difference?
I thought "codzień" worked liked the compound adjective in English, "everyday".
"Co dzień" (an adverbial expression) is written separated. Likewise, you write separated 'co noc', 'co tydzień', co miesiąc', 'co rok'. In spite of that, you write jointly the compound adjectives or adverbs such as 'codzienny/codziennie', 'coroczny/corocznie' etc.
True, it should be written separately. However in the past (before the 70-ies or so) it was not a norm and you can find many instances of such usage in older texts. My guess is that once it had been written as compound word because the (in pronunciation) stress falls on "co", making this syllable quasi-penultimate. Cnf. "co rok" where the accent falls on "rok".