서른
seoreun · TOPIK 1
thirty
서른 = 셋 (three) + old tens ending -흔/-른; the s- of three survives
Native Korean tens grow from their units: 셋 (three) gives 서른, just as 넷 gives 마흔 and 다섯 gives 쉰. Keep the starting s sound of 셋 and add -reun. Sound hook: so-run, as in so, run thirty laps.