The topic marking particle will either be ~은 or ~는, depending on whether the noun or pronoun ends in a consonant or vowel. 미니 is a name ending in a vowel. Therefore the topic marking particle that will be used is ~는. 정민 is a name ending in a consonant. The topic marking particle that will be used with consonants is ~은. The topic marking particle always comes after the noun or pronoun, never before it.
When do you use the topic marking particle? You use it when you want to change the topic or subject of a conversation. For example, let’s say two women are talking about what their children are doing now.
Woman 1: 현빈이 지금 자요 (Hyunbin is sleep(ing) now)
Woman 2: 그래요? 준수는 지금 공부해요 (Oh really? Junsu is study(ing) now)
Words used in the conversation: 지금 = now, 그래요 = really? 자요 = sleep, 공부해요 = study.
The first woman used the subject marking particle after her son’s name 현빈. In her case, 현빈 was the subject of her conversation. (Subject marking particle is 이 because 현빈 ends in a consonant. For more on the subject marking particle, look back at the last month’s posts ). However, the second woman used the topic marking particle 는 after her son’s name 준수. The second woman wanted to change the topic of her conversation to her son and what he is doing. That’s why she used the topic marking particle instead of the subject marking particle.
So whenever you have a shift in the conversation, you’ll use the topic marking particle instead of the subject marking particle. When the topic of the particle hasn’t changed, you won’t use the topic marking particle, you’ll just continue to use the subject marking particle. However in reality, especially in conversation, the subject marking particle can be easily omitted. This is especially true when the subject of the conversation is obvious to both parties.