Add Arial
The default font stacks of the Mapbox GL style specification are Open Sans Regular and Arial Unicode MS Regular. They should be somehow covered (or aliased) by the fonts here.
"text-font": {
"type": "array",
"value": "string",
"function": "piecewise-constant",
"zoom-function": true,
"default": ["Open Sans Regular", "Arial Unicode MS Regular"],
"doc": "Font stack to use for displaying text.",
"requires": [
"text-field"
]
},
Arial Unicode MS Regular is a licensed font - not free.
Alias to the Noto font is probably the only free solution - can be done on server side by TileServer GL. The problem is that Noto is not designed the way that one font file contains all characters. The number of glyphs is too large. Minimally two different fonts are required.
The latest Noto we released does have all required characters. https://blog.klokantech.com/2018/02/maps-in-the-language-of-visitor.html