jatls

The regex characters you have pointed to are simply there as a redundancy to ensure that all terms are identified correctly. What you have referenced is actually called after the term is first identified.

I have little experience with non-Latin character sets however I don’t see a reason why the search function should fail. As long as the title of the glossary item exactly matches the term in a post it should be found. The first thing I would check is that the database is properly storing your terms and that your posts do contain the exact match. The reason I say to check the database is that often times the software will display the information differently than it is displayed. If WP is doing some sort of character conversion then that may be the cause of the problem.

For your reference (and so you can do any checking/testing) the regex that identifies search terms is as follows:
'/\b'.$glossary_title.'s*?\b(?=([^"]*"[^"]*")*[^"]*$)/i'
While this looks complicated, it simply searches for the glossary term (plus or minus an ‘s’ character for plurals in English – which is completely optional so that wont affect anything with foreign languages) between word boundaries. The part in brackets at the end excludes it from searching within the tooltip when enabled and the /i at the end makes sure the search is case insensitive.

I’m happy to make any changes if necessary but I cannot troubleshoot these problems with my current setup. Any assistance with troubleshooting and identifying any changes would be much appreciated.