This is the 14872nd most frequent Korean word.
박태환이
"박태환이" refers to "Park Tae-hwan," a South Korean swimmer and Olympic medalist.
In this sentence, 박태환이가 is the subject of the sentence and indicates the person performing the action of winning the medal.
박태환이가 올림픽에서 금메달을 땄다.
Park Tae-hwan won a gold medal at the Olympics.
Here, 박태환이를 is the object of the sentence and indicates the person I want to meet.
나는 박태환이를 만나고 싶다.
I want to meet Park Tae-hwan.
In this sentence, 박태환이랑 indicates the companionship or association with Park Tae-hwan for the activity of learning swimming.