Regarding character encoding in MotionBuilder Python, there are two considerations:

• If you edit a script outside of MotionBuilder, it must be encoded with UTF-8 before you can open it in the MotionBuilder Python editor.
• The Python interpreter: by default, Python assumes all scripts are written in ASCII. To use Unicode (e.g. to write a language other than American English), declare the encoding in the first or second line of your script like this: # coding=<encoding name>. This line may not contain any Python statement. For more details, see "PEP 0263 -- Defining Python Source Code Encodings" at python.org.