The best answer I can determine so far is that there is something about Georgian and keyboard entry that tk does not like, at least not on Windows.
Character 'translation' is usually called 'transliteration'.
Tk text uses the Basic Multilingual Plane (the BMP, the first 2**16 codepoints) of Unicode. This includes the Georgian alphabet. The second image shows that the default Text widget font on your system is quite capable of displaying Georgian characters once the characters are in the widget. So a new display font does not seem to be the solution to your problem.
('ქართული ენა' is visible on Firefox because FF is unicode based and can display most if not all of the BMP.)
It looks like the problem is getting the proper codes to tk without going through your editor. What OS and editor are your using. How did you enter the mixed-alphabet line similar to
txt.insert('1.0', 'ქართული ენა') # ? (I cannot copy the image string.)
How are you running the Python code? If you cut the question marks from the first image and insert into
for c in '<insert here>': print(ord(c))
what do you see?
You need a 'Georgian keyboard entry' or 'input method' program (Google shows several) for your OS that will let you switch back and forth between sending ascii and Geargian codes to any program reading the keyboard.
Windows now comes with this, with languages activated on a case-by-case basis. I already had Spanish entry, and with it I can enter á and ñ both here and into IDLE and a fresh Text box. However, when I add Georgian, I can type (randomly ;-) ჰჯჰფგეუგსკფ here (in FireFox, also MS Edge) but only get ?????? in tk Text boxes. And these are actual ascii question marks, ord('?') = 63, rather that replacements for codes that cannot be represented. Japanese also works with tk-Text based IDLE. So the problem with Georgian is not generic to all non-latin alphabets.