We have not encountered issues with the search in multilingual in version 5.3. If you are using version below 5.1, please upgrade to the latest version.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items