I'm a Korean. I heard that avidemux is good. But I can't find Korean translation of avidemux. :-[
No, unfortunately only the Qt translations are included (the file qtbase_ko.ts in https://github.com/mean00/avidemux2/tree/master/avidemux/qt4/i18n (https://github.com/mean00/avidemux2/tree/master/avidemux/qt4/i18n)), so mainly just ì·¨ì†Å' / Ãâ,,¢â€¢Ã¬Â¸ in some dialogs are localised if you launch Avidemux with the Korean locale.
export LANG=ko_KR.UTF-8
avidemux3_qt5
Do you have experience in localizing software? Would you like to write one? You take avidemux_en.ts, rename it to avidemux_ko.ts, replace
<TS version="2.1" language="en_US">
with
<TS version="2.1" language="ko_KR">
using a decent text editor (vim on Linux, maybe notepad++ on Windows) and start replacing
<message>
<location line="+1"/>
<source>Play</source>
<translation type="unfinished"></translation>
</message>
with e.g.
<message>
<location line="+1"/>
<source>Play</source>
<translation>재ìÆ'Â</translation>
</message>
(never touch anything within the source-Tags!).
I'm not a Korean despite my nick, I can't help here.