A wild guess is that the PHP installation was somehow automagically picking up the environment variable off of its Linux host, which had the locale variables (LANG, LC_*, etc) set up to C (which is Linux' way to say it is using ASCII for some reason I don't really get).

:: @Jose Pedro Arvela added on 16 Jan ’14 · 14:41

Probably because it is ANSII C or something like that.