Linguistic oddity

I was working on a foreign law title today and discovered an interesting linguistic shift. The title was Turkish, so I found our foreign language guide that listed the various basic stuff for most languages, like months, days of the week, seasons, etc. Those are very useful for setting up patterns for checking in journals. The guide listed the months, no problem, except that they didn't match for October through January. According to our one contractor, whose wife speaks the language, Mustafa Kemal Ataturk spearheaded the language shift in the 1920s, completely overhauling Turkish so it was more Turkish than Arabic, eliminating language borrowings. The guide was published in the 1930s so I'm guessing the changes came during that period. (It reminds me of the movement in French to purify it of the "le hot dog" type words.)