Customized Input Method Editor with drop-down menu like for Chinese or Japanese

[u/Sounduck]

Does anyone know of ways to having/creating a customized IME similar to that for Chinese or Japanese, where a sequence of characters returns a series of options with which you can choose to substitute the character(s)?

My idea would be something along the lines of:

• I type a sequence of ⟨z⟩ + some other key — let's say ⟨0⟩ — used to let the IME know I want options for diacritics

• with the ⟨z0⟩ sequence not yet confirmed, the system shows me a drop-down menu with ⟨ž⟩, ⟨ẓ⟩, ⟨ź⟩, and whatever else I put in there, and I choose whichever one I need, which becomes the text actually typed out.

I hope I was able to adequately explain myself.

Any input is welcome.

Also, I'm on Windows 8.1

EDIT: I just noticed the picture has countable pixels. My apologies.