Is it possible to create some sort of "symbol shortcut" in Word?

I’m rewriting a text in Word from another document. The text I’m supposed to type in basically consists of two different alphabets that are mixed up.
Now, I use one alphabet in the keyboard, and the graphemes from the other alphabet are in the “Symbol” section.

Considering these are mixed, I basically have to go every few second in the Symbol section and insert the symbols I need.

What I ask is, it there any way to make a “symbol group” and use those symbols I need with shortcuts, (For example, get a š sign by typing Shift+s or something like that) or do I need to insert it from the Symbol section every time? It would make my typing much faster if I could make some sort of a shortcut, where I could type the symbols I need from the keyboard…

And this is a long document I need to rewrite…