Similarly "I've been here since two days" is usually a giveaway that somebody's translating from French.
“Ich bin seit zwei Tagen hier.”
I wouldn't be surprised if it were most languages really, English 'for' seems the weirder construction.
You could get away with it in speech since it sounds like 'since.. [thinking] two days ago' and it's acceptable to change construction like that in casual speech, but written it doesn't seem right to me.