The UT Libraries' catalog only recently––in the history of library cataloging, that is––started to add the original scripts to catalog records. The bulk of records are found only in transliteration, following the Library of Congress standards.
If you wish to search in the UT Libraries' catalog in the original script, it is recommended to start your search in the OCLC Advanced Search database (also known as WorldCat). Then limit your search using "Limit availability to" and "items in my library." Best practices include searching by title and/or author in the original script; keywords in original script will not be as effective in the OCLC database.