[jaclaz]

Yes and no (meaning that we strangely use both Arabic and Turkish in different situations).

If you don't understand, you would say "Mi sembra arabo" (it seems arabic to me) but if you are talking and the other part doesn't understand it is more common "E che parlo, turco?" (what am I speaking, turkish?) than "E che parlo, arabo?" (what am I speaking, arabic?) at least in my experience.

Of course historically "turk" and "arab" were synonyms due to the fall of of Constantinople and the "contacts" with the Ottoman Empire.

And now, risking to quote myself, evidence of the sentence (by a greek) "it's English to me":

https://news.ycombinator.com/item?id=20484479#20485258

[pmontra]

I never heard this Turkish expression, only the Arabic one. I always lived in the Milan area. Where is it used? "E che" sounds central Italy.

[jaclaz]

Sure, the "E che" form is tuscany and central Italy (as often happens considered archaic by someone), the "parlo turco" is italian alright:

http://www.treccani.it/vocabolario/ricerca/Parlare-turco/

A more "neutral" Italian would be "Parlo forse turco?".

Curiously, it is a sentence used in literature by Andrea Camilleri which should mean that the form is also in use in Sicily.

JFYI ;-) Mario Vigorone [1980]:

https://www.youtube.com/watch?v=4yANFI1bs9c

[pibi]

Also the "parlo arabo?" is listed on treccani: http://www.treccani.it/vocabolario/arabo

BTW, I agree with the other comment that this is more common in the north.