If one were to switch to a non-latin language in a text, such as Chinese or Japanese, how would you tell the reader when the other language starts and ends? In Japanese, there is a symbol to mark English letters and words but I haven't found anything similar in English.
Would you please send a scan of one or two print pages? There may not be a direct provision for this situation but I can't tell unless I can see the actual print you are working from. When I see the print I can give you some specific answers and recommendations.
Also, please let me know what braille rules you are using. Do you have the NBA Interim Manual for Foreign Language Braille Transcribing?