I tried the same thing on my map, and at first I thought I was seeing the same results. However, changing the language can sometimes be subtle, especially if you just look at a high-level map of the world, because many country names are the same. Of course, it is very easy to see the difference for the Japanese, because this language uses a different character set.
The easiest way I've found to quickly check for a language change is to notice which map controls you have displayed on your map. I show the parameters Satellite, Terrain, etc. In the upper right corner of my map. And with that, you can quickly see that the language has changed.
I confirmed:
- Arabic (ar) - This one also has a different character set, but country names do not change
- Japanese (ja)
- French (fr)
- German (de)
It works for me, it just cuts a bit to notice the changes. Google maintains a list of supported languages, and for those languages that do not change labels on the map, here is a quote from Google Docs:
The controls and directions of the map in the Directions Panel have been translated to a subset of the languages listed in the Supported Spreadsheet Languages. Shortcuts on maps are presented in the preferred language when translations are available.
More information about this particular moment, in particular about the map labels, is included at the bottom of this answer.
The following is an example of map shortcuts after setting language=de :
Note the differences in the labels for: Deutschland, Ceska rebublika and Polska.
And here is an example of shortcuts without a language setting (by default in English due to my browser settings):
Note the differences in names for: Germany, Czech Republic and Poland.
Here is a frame showing China and Japan using `language = de ':
Many stickers on the map are displayed the same in any language, but there are many differences. The reasons for the differences are explained in this final explanation, directly from Google support:
By setting the language parameter, you redefine the client’s preferred browser language. With the API, this means that any interactions between the API and the client’s browser (dialog boxes, etc.) will be displayed in the specified language - provided that the language is supported.
For the names of real places (map labels), we use the same data as maps.google.com. It makes no sense to translate the names of places in Australia to (say) German, and it makes more sense to offer translations into Japanese and Chinese characters, where names in Latin will be otherwise illegible. Having said that, Greek and Arabic (and possibly others) have not yet received global translations - presumably due to the smaller audience.
So, we summarize:
- The translation of the Maps API is mainly related to the interaction of the API with the client browser.
- Google is working harder to provide global coverage for non-lingual languages.
- Not all non-Latin languages enjoy global support.