I am also named Yitzhak Aizic and that is how I am called up to the Torah. But I believe that Bob Malakoff simplified his explanation. On my birth certificate in latin letters I am listed as Aizic (Romanian spelling) but in the USA for instance when you pronounce the name it sounds like the non Jewish Biblical translation of the name Isaac, bottom line not always does it mean that it is the "Yiddish," translation we will probably never know how, why and who started this double-barrel name.
But maybe the discussion should be more on the history and reasoning of Jewish double barrel names. I'll just give a few in order not to bore you. Ephraim Fishel
Originated in Goshen, Egypt when Ya'acov blessed his grandson Ephraim that his descendents would increase like the fish in the ocean. Another double barrel name taken from our Bible, Yisaschar Bear. Yisaschar one of the sons of Ya'acov and a tribe is named had a donkey on its emblem. (again due to the blessing of Ya'akov which he gave to his son. Now somewhere along the ages our ancestors decided that they did not want to make an "ass," of themselves by calling their son also "donkey," so they chose Bear which was an animal strong like a donkey.
Lat but not least Kalman Klonymous. Klonymous is a name taken from the Greek period (Like all those called Alexander) The meaning of the name Klonymous is a "good name," or in Hebrew "Shem Tov" How did Klonymous get to Kalman I really don't know. My guess is that our forefathers found it difficult to pronounce Klonymous (without having to go to a dentist afterwards) so they found an easier way to pronounce that name. Wishing y'all good health during this crazy Pandemic.
Lone Magen David Star State of Israel