Did you understand what your Italian friend meant when he/she told you: “Am I speaking Turkish here?”
When in Italy during a conversation a person can’t get their point across they attribute ironically the resistance of the interlocutor to lack of understading of what has been said, and Turkish here stands for an incomprehensible language. The origin of the idiom is clearly due to the contacts among people around the Mediterranean and the difficulties often arising in the practices of trade (particularly in the Levant). This clearly shows when the sentence is heard in the same context but Turkish is replaced by Greek and Arabic (other languages commonly spoken in the Levant).
Notable exception is the phrase “Do I speak Ostrogoth?”, which means the same but is clearly suggestive of the disconcert and confusion of the Italians after the fall of the Roman Empire, when Germanic populations began to spread uninvited in the country.
Source: Giorgio Bellini from Italy