Should we use English or Portuguese on tags? Or should we use both as synonyms?
You can get some ideas from the same question in spanish.stackexchange.
The current situation is that almost all tags are in Spanish, but descriptions are in both languages (spanish + english).
I think that would be the best for anybody learning portuguese.
tag language on other language sites
Italian.SE (English) Russian.SE Russian Chinese.SE (English) Spanish.SE Spanish French.SE French Japanese.SE (English) German.SE (English)
I'm all for having our main tags in Portuguese. The meaning of most tags should be obvious to English speakers and if necessary, we can create "tag synonyms". That way, if someone uses an English tag like verbs, which is a synonym of the Portuguese verbos, the question will automatically be tagged with the Portuguese tag.
By conforming to the new orthography, there shouldn't be much confusion as to whether we use European or Brazilian Portuguese.
Unfortunately, we don't seem to be able to request a Portuguese UI (see comments on this answer), but at least Portuguese tags are one step toward the "full immersion" recommended in that answer.
As a learner of Portuguese, having come from an English background, I believe the tags should be synonyms. As a person who has a question about something in Portuguese, I inevitably will tag my grammar question as grammar, as I
1) Don't know that gramática exists
2) If I do know, I may or may not have the ability to type the á (or any other accent) character on my keyboard.
Thus, having my question be automatically assigned to gramática is immensely helpful in making sure it will be visible and, ultimately, receive answers.
One of the solutions pointed out so far (actually in the form of a duplicate which was closed later on) is to go and restrain our set of tags to Portuguese names, burninating those in English (such as discussion) and keeping a description in both languages. Initially, I agreed to this approach. However, when attempting to place myself on the position of a learner, finding the right tags may be a bit too tricky, and either lead to more poorly tagged questions or extra effort from other users having to correct them.
Since it's unlikely that these tags will form a semantic collision, I would suggest keeping them as synonyms, thus keeping it friendly to learners without crippling the purpose of tagging. This should also apply to different forms of writing in Portuguese (the Brazillian Portuguese sinônimo and the European Portuguese sinónimo are synonyms), in which a decision for main tag is required.