We've got a new volunteer, Chiefwei, taking care of Chinese language conversion stuff starting from months ago. One problem is that some localization data (namely the conversion table) resides in the codebase while it needs maintenance from time to time based on user feedback. Although Nikerabbit helpfully merged many of these patches, there's always a delay on this which is sometimes not short. Thus, I'm considering applying for +2, so I can review such patches myself as a native speaker and merge them, improving the efficiency of these maintenance tasks.
There should be consensus from existing project owners. In the future it'd be better if there was at least one other person with +2 in mediawiki/core to chime in with support. (For the record, I support liangent's request as well.)