Answer
INCHEON’s UMMADA wichi means ‘INCHEON’S MOM’ in Korean
Explanation&Learning Korean
The phrase “인천 앞바다” (Incheon’s front sea) sounds like “인천 아빠다” (Incheon’s dad) because “앞바다” (front sea) sounds similar to “아빠다” (dad). Therefore, humorously, the opposite of “Incheon’s dad” is made to be “인천 엄마다” (Incheon’s mom). This kind of pun, based on similar-sounding words, is typical in Korean dad joke