남자"예"요 vs 남자"에"요 Your understanding is correct. 이에요 and 예요 are tricky and a lot of Koreans don't use them right. In speech, they are indistinguishable most of the time, which adds to the problem. Anyway, here's a recap of the rule. * original form: -이다 (particle). It can take the form of 입니다, 이다, 이에요/예요, 이야. * + 이에요 cases 1) Noun ends with 받침: => N+이에요 (학생이에요, 교실이에요). It cannot be 예요. 2) Noun ends with vowel: => N+예요 (친구예요, 학교예요). It should not be 이에요. * reason: the other cases(햑생예요, 친구이에요) are phonetically difficult or unnatural. There are some tricky cases. * the adjectival verb 아니다 ("is not") can take on the -에요 ending, resulting in 아니에요. This is a different construct than +이에요. One should not mix up the two. So we cannot expect all 에요 to be part of 이에요. There are other -에요 cases. * A confusing case with people's names because of the way they are called. If a name ends with 받침, we always refer to the name by adding "이" to the name: 영희한테 말해 vs 영숙이한테 말해 (again this rule is there to make pronunciation smoother). So when a 받침-ending names form +이에요, the base name becomes +이 (영숙이), after which 예요 is added according to rule #2 above , resulting in 영숙이예요. This can be confusion because looking at just the name part "영숙" only, it appears like 이예요 was added. But "이" is part of the noun itself in this case, so it is following the same rule.