[still_grokking]

> .i => ι

That's more or less what the compose key does (but works everywhere and not only in EMACS). :-)

Only that there isn't such combination defined by default. But adding it is trivial:

  <Multi_key> <i> <i>                 : "ι"   U03B9    # GREEK SMALL LETTER IOTA

This line in your ~/.XCompose and you can type "ι" by pressing compose-i-i without changing the whole keyboard layout away form your default.

I'm using the compose key the whole time to input "special symbols"™. It's very intuitive. (Like, for example you get the "™" when pressing compose-t-m).

I have the compose key on the otherwise useless CAPS-LOCK (and CAPS-LOCK on/off by pressing left and right space simultaneously). Both options are only ticking a check-mark away when using Linux.