I have literally visited the entire wiki and the beginner’s guide to search about my problem but have never seen a real solution.
The problem is that I use the interface in Spanish, but I want to see countries like Japan, Korea or just some of the Middle East but all the translations are in the original language of the place in question without a way of seeing what it is called in English or Spanish.
Is there any possibility to change the language of all countries to the Roman alphabet?
In the Android world, I know Locus Map Pro with either their own maps or those from openandromaps.org handles languages well. These are offline maps. In a well-mapped place like Hong Kong, I can switch between all Chinese, all English, or the local convention which is Chinese followed by English. I imagine Spain etc. would be similar as Europe seems to be quite well mapped (with mappers correctly using name, name:en, name:es, etc.)
At https://cloud.maptiler.com/customize/ You can choose the language, modify the look&feel and save your style - this gives you raster & vector OpenStreetMap tiles for use in mobile phones or websites with all the libraries typically used (Leaflet, Mapbox GL, OpenLayers, etc).
All powered by open-source code and OSM data - if you are keen to know how is it done exactly check https://openmaptiles.org/
you can get the Spanish or English version of osm-carto like tiles (as used by www.osmap.es or www.osmap.uk ) through the maptiles api.
Do you use this in a webpage context? If so, do you use openlayers or leaflet?
So you would just need to get an api key from www.maptilesapi.com (for private or hobby use there is a free plan available) and then integrate the tiles - an example for leaflet can be found here. For Spanish tiles, replace “en/map” with “es/map” in the TileLayer URL.