Academic plagiarism rules and ESL learning - Mutually exclusive concepts?

My interest in the relationship between anti-plagiarism rules and ESL learning arises out of my own lack of training regarding plagiarism. As someone who has been out of the academic community for more than 30 years, I came to a course in English Language Teaching with only the vaguest notion of the meaning of plagiarism. Although I have practiced commercial law for three decades and am presumed to have a good command of the English language, I found myself struggling to comply with complicated citation conventions and to understand the meaning of such terms as "a distinctive name” and “a phrase", found in American University's Academic Integrity Code (Section II A). How much more difficult is this struggle for someone whose native language is not English, I wondered.