Awesome

fcitx-hangul

Hangul Wrapper for Fcitx.

Using with non-qwerty English system layout

The addon handles key input based on its string value, not keycode, so pressing t in Colemak is interpreted as ㅅ rather than ㄹ for Dubeolsik. To fix this, set Default (qwerty) layout for Hangul.

Via fcitx5-configtool: in Input Method tab, select Hangul, then press Select Layout and choose Layout: English (US), Variant: Default. Or edit profile config file:

# group and item numbers may be different
[Groups/1/Items/0]
Name=hangul
Layout=us