The more you adhere to standard phraseology, the better off you'll be.
I work at a large airline and at the start of a trip I find myself flying with someone I've never seen before more often than not. On the first flight, each pilot is assessing what/who they've got to fly with for the trip. I get a warm fuzzy when the other guy contacts departure and says, "Departing two thousand one hundred for one one thousand," as opposed to "Two for eleven".
Thank God international flying is in English. There, rigid phraseology discipline is non-negotiable if you want to ensure a smooth flight experience. Zee-roe, not Oh.