Big work lost! Not funny at all
This site is for questions and answers about LibreOffice usage. Yours is not even a question. Nobody here is interested in what is funny or not to you. Read these guidelines and ask a good one. So far, get a downvote.
The format .csv is text only. Wikipedia Comma Separated Values
Always save in native format .ods and if you need something saved in another format do a Save As from the .ods
Al
If you use .csv which is a text file and defaults to ISO-8859-1 character set. If you wish to use Tibetan you must specify the character set to use, for example UNICODE(UTF-8) which is the set used in normal .ods and supports the Tibetan characters.
Why are you using .csv?