I’m fairly certain non-english keys in tags are not allowed, but it isn’t stated anywhere in the wiki. I wanted to reprimand a mapper who uses Chinese keys, now I’m getting a bit less sure about my case.
https://wiki.openstreetmap.org/wiki/Tags
https://wiki.openstreetmap.org/wiki/Any_tags_you_like
It’s about this key: http://overpass-turbo.eu/s/sEP
If the attribute really was specific to the country, it might be valid, but this appears to say Chinese Administrative District, which would seem to be just an admin level to me and should use the standard tag.
Non-English keys should be avoided, so your intuition is correct. A possible exception might be concepts that have no English equivalent, but that does not appear to be the case here.
OSM is more likely to rely on unwritten rules when compared with other projects, so it’s not that surprising that this convention is not explicitly documented (although it’s just as likely that it’s somewhere in the wiki and I’m just not finding it).
In this particular case the information contained in 中国行政区划=* is duplicated in the tag china_class=* (at least for some locations I checked). So not only is this a non-english tag, information is also kept redundant.
I hope you are not serious about the “reprimand” bit, please simply point out to the mapper in a friendly manner that the convention is to use English keys (and likely that they are duplicating existing information).
You might further want to point out that the language and script of the key has nothing to do with how it is presented to users on maps and in editors (where keys are often translated).
Simon
Sure, I always assume good intentions 
The mapper in question is active in a discussion with other local mappers, there’s currently a proposal for a proper new tag, so once that’s finished we can start replacing these tags.
Why does it need a new tag. What is wrong with http://wiki.openstreetmap.org/wiki/Tag:boundary%3Dadministrative
Hi! What is the status of this issue? Did mapper reply?