Mongolians often use Roman letters for texting.
This program converts Cyrillic to Roman letters.
Some variations exist and you may edit the replacement list in the script accordingly.
The script can only convert from Cyrcillic to Roman letters, not the other way around (because that could not be described by a function since "i" can be И, Й, Ь, Ы or Ъ)
Python IDLE is based on Tkinter and has an unfortunate bug that converts the letters Ү (Cyrillic Straight U) and Ө (Cyrillic Barred O) into a question mark when typed in from the keyboard. You can use an IDE that avoids Tkinter e.g. Spyder. I also found a solution on how to get back those letters in Python.
Standard Replacment list (char_to_replace_1):
| Cyrillic | Roman |
|---|---|
| А | A |
| Б | B |
| В | V |
| Г | G |
| Д | D |
| Е | E |
| Ё | Yo |
| Ж | J |
| З | Z |
| И | I |
| Й | I |
| Ө | U |
| К | K |
| Л | L |
| М | M |
| Н | N |
| О | O |
| П | P |
| Р | R |
| С | S |
| Т | T |
| У | U |
| Ү | U |
| Ф | F |
| Х | H |
| Ц | Ts |
| Ч | Ch |
| Ш | Sh |
| Ь | I |
| Ъ | I |
| Ы | I |
| Э | E |
| Ю | Yu |
| Я | Ya |
Replacement list according to Standard MNS 5217: 2012, source: https://estandard.gov.mn/standard/reader/4635
| Cyrillic | Roman |
|---|---|
| А | A |
| Б | B |
| В | V |
| Г | G |
| Д | D |
| Е | Ye |
| Ё | Yo |
| Ж | J |
| З | Z |
| И | I |
| Й | I |
| Ө | Ö |
| К | K |
| Л | L |
| М | M |
| Н | N |
| О | O |
| П | P |
| Р | R |
| С | S |
| Т | T |
| У | U |
| Ү | Ü |
| Ф | F |
| Х | Kh |
| Ц | Ts |
| Ч | Ch |
| Ш | Sh |
| Ь | I |
| Ъ | I |
| Ы | Y |
| Э | E |
| Ю | Yu |
| Я | Ya |
Glossika differs again in the following:
| Cyrillic | Roman |
|---|---|
| Е | Je |
| Ж | Zh |
| Й | J |
| Х | X |
| Ю | Ju |