Removing correct and valid data from OSM is not ok. Add name:cy, where it is valid is fine but in general the primary language in Glamorgan is English.

Other than a literal translation, what is the source of this name:cy?

What is the source of this name, beyond a literal translation?
The wikipedia page you have added does not exist.

What is the source of these name beyond a translation?

It is kind of unlikely that there is a Russian name for a small town.

Removing correct data from OSM is not acceptable, the name tag is required by many of the applications which use OSM data.

I have reverted this changset.

Wikidata tags are intended to not be language specific and therefore wikidata:cy pointing to the same page serves no purpose.

Also beyond a translation what is the source of this edit?

Names restored

Names restored

Name restored

Names restored

Names restored

Please do not remove correct data, I have restored the names.

What is the source of these names?

The above comment applies to the English places however removing correct data and adding incorrect data into the tag is not acceptable.
Please remember that OSM is in active use and such changes are damaging to those who use our data.

I have reverted this changeset.

What is the source of this name, is there any evidence of actual usage beyond a translation?

What is the source of this name? It disagrees with wikidata.

What is the source of this name? It disagrees with wikidata.

What is the source of this name, is there any evidence of actual usage beyond a translation?

Names retored

What is the source of this name?