Currently we have RadDiagnostics localized for English and German and for now we don't have plans for adding more languages. If you want to display the component in a different language, you can use some of our localization mechanisms descibed here
. The keys of the strings that are used in the Diagnostics component are: Diagnostics_MessageBox_Title, Diagnostics_MessageBox_Content, MBYesText, MBNoText.
I hope this information helps. Let me know if you need additional assistance.
All the best,
the Telerik team