There are a contradicting rule on wiki about multilingual translation (especially for Iran, Farsi language).
In one hand:
Taking Moscow as an example, the wiki on Names argues that (under Repeating name with language specific tag section) instead of:
We should prefer:
Meaning that when a translation for a node (in this case name:en) in some other language is provided, we also should provide a translation in the original language (which means name:ru) with the same value as name tag.
This is in par with KeepRight 360 rule that marks a warning for the nodes that lacks such tag.
On the other hand:
The guideline provided in Iran Tagging wiki doesn’t mention providing such tag. To be fair, it recommends using full_name which seems to be a deprecated tag. So this page could be outdated and should be taken with grain of salt.
What is more concerning is the rules in Multilingual_names wiki which states the rules for each country but they are doesn’t match in this regard and a few of them contradict with the rule I mentioned in Names wiki article. For instance, both Kuwait and Lebanon have Arabic as their official language so they are expected to follow similar rules.
The rules for Lebanon is on par with the wiki and KeepRight which demands providing the original translation in a dedicated tag:
However, the recommendation for Kuwait doesn’t follow this:
I would say, there is no need to take action if you encounter such a situation. Additionally, I do not read in the text that one version is preferable.
full_name=* seems to me a tag specifically for reflecting the situation in Iran as there are apparently two names on the street signs (?). Where does it say it is depreciated?
Please also observe that the country-specific rules are country specific. Some countries face situations where some minority speaks their language, but the national government uses a different one. In such situations, these recommendations might contradict the more general documentation, because maybe there was a consensus of local mappers with regards to their languages spoken or the legal status of minority languages.
I argue that this rule should be followed when creating new nodes as it implies we should have repeated translation as their tag. On the other hand, we should not have different standards whether we are creating a new node or modifying and existing node, therefore the same rules should to existing nodes too.
Also, KeepRight has dedicated a rule specifically for this case to generate warning. OSM web editor has integrated KeepRight as one of its main issue detectors.
The streets in Iran mostly have a single Farsi name on the sign and sometimes there is English transliteration text available too. I assume full_name is deprecated as there is no reference to it in the wiki.
Sure, I understand that rules might be overridden for each countries. I am curious why this general rule is not followed by Iran though, because I cannot see any reason not to.
Well, as I said, I understand the article the way that this is not a rule, but a suggestion to avoid the following:
In case there are just name=* and name:en=* in a not English speaking area which are different. One could come up with the idea to add name:ab=* (ab being the abbreviation of the local language) to every named object in the area.
And the vice versa case: removing all name:ab=* because they are equal to name=*.
Please remember that KeepRight is a quality assurance tool, but you should not follow it blindly. Sometimes, there are reasons why things are “wrong”.
I suggest you discuss that with the fellow mappers in Iran because I can not help you there. You can reach them in their dedicated forum 103 or via their talk-ir mailing list.