Set tile layer language

i like the maps app really a lot, think it´s a beautful gimmick for a nice display of fotos and a god alternative to google maps in the country where i live.
My problem is, that i would love to even use it as an actual map of the world, but as i dont know chinese, arabic, cyrillic or greek letters, i cannot use to browse different countries. **Thats what i need:** To be able to use the app for the whole world, i need to change the language to a language that i know. **Thats what i dit so far:** So far i made the app use another tileserver, that doesnt by default print the names in the countries language, but uses preconfigured tiles in the language of whish (as is possible in Gpxpod). for that i changed the leaflet tile-server for the Base-Layer (in scripts.js, layer.js…) to fetch its data from the german osm-tile server.
Thats the problem i still have:
Nether the style of the map, nor the names of the places change accordingly.
thats what i suspect:
In scripts.js it looks like the data-layer for the osm tiles is disabled and mapbox/streets-v8 is added as an overlay, but i`m not sure about that.
Thats where i need help
if my assumption is right:
How do I disable the mapbox layer and display the osm-tile-Data?
if my assumption is wrong:
where else could I possibly change the naming parameter, so places would be displayed in german?

Already thanks for trying to help,