Complex sentence: Greek Jews historically tended to follow the Jerusalem Talmud instead of the Babylonian Talmud, and developed their own Minhag and their own variety of Greek language, called Yevanic.
Split into simpler sentences: Greek Jews historically tended to follow the Jerusalem Talmud instead of the Babylonian Talmud. They developed their own Minhag and their own dialect of Greek language, called Yevanic.