Most Linux environments already have this, it's called "compose key". You may need to enable it in your desktop environment's settings, but then after pressing the key you can press !? to type ‽, 12 to type ½, <= to type ≤, n~ to type ñ, <3 to type ♥, etc. Here's GTK's list: https://help.ubuntu.com/community/GtkComposeTable

It would be nice if this were built into Windows, but in lieu of that, I have been using WinCompose[0] for several years for typing diacritics (as part of my learning French). For example:

* ALT e' = é

* ALT u " = ü

* ALT n ~ = ñ

It's not limited to diacritics; you can type ligatures (ALT ae = æ), extended characters (ALT [/] = ), I assume the majority of UTF (ALT #G = 𝄞) and so on. And yes, even emoji (ALT ALT alembic = )

edit: apparently, HN won't show the checkbox (U+2611) or alembic[1].

[0] http://wincompose.info/

[1] https://emojipedia.org/alembic/

For Windows, the ENG-INTL keyboard layout is pretty good for simple accented characters, covering latin-based European languages [1].

Windows+. also allows you to just type to search for emojis, so e.g. typing WINDOWS+. sad ENTER gives you a sad emoji. Sadly this doesn't work for symbols, even though the Windows+. menu has a good coverage of symbols.

I guess you can always switch your keyboard to Korean input.

1: https://community.windows.com/en-us/stories/keyboard-shortcu...

Julia does this in a pretty simple way, you type \lamdba then press tab and it becomes λ, emojis and many other things work like this, so typing them is very wasy.