[Bug]: localizeLabels doesn't support most Mapbox languages (e.g. nl, pl, el) and has no effect on the Standard style #4326

Mapbox Version

11.23.1

React Native Version

0.84.1

Platform

iOS, Android

@rnmapbox/maps version

10.3.7 (main)

Standalone component to reproduce

import React from 'react';
import { MapView, Camera } from '@rnmapbox/maps';

const BugReportExample = () => (
  <MapView
    style={{ flex: 1 }}
    styleURL="mapbox://styles/mapbox/streets-v12" // also try "mapbox://styles/mapbox/standard"
    localizeLabels={{ locale: 'nl' }} // also try 'pl', 'el'
  >
    <Camera defaultSettings={{ centerCoordinate: [12.0, 50.5], zoomLevel: 3.6 }} />
  </MapView>
);

export default BugReportExample;

Observed behavior and steps to reproduce

1. Render the component above with locale: 'nl' (or 'pl', 'el') on the Street style.
   • Labels stay in English (or in the previous language when switching at runtime).
   • iOS logs: RNMBXMapView.applyLocalizeLabels() MapError: Locale: nl (fixed nl) is currently not supported
   • Android logs: [maps-android\LocalizationPluginImpl]: Locale: nl is not supported.
2. Switch to the Standard style (mapbox://styles/mapbox/standard) and use locale: 'es'.
   • Labels stay in English even for a "supported" language.
3. (Android) Render with localizeLabels set, then remove the prop.
   • The app throws Dynamic value from Object is not a ReadableMap (RNMBXMapViewManager.kt:133).

Reproduced on the example app: iOS simulator (iOS 18.6) and Android emulator (API 35).

Expected behavior

localizeLabels should work for every language listed in the Mapbox internationalization docs
(43 languages, including nl, pl and el), on both classic styles and the Standard style:
https://docs.mapbox.com/help/dive-deeper/maps-internationalization/

Removing the prop should reset labels to the default language without crashing.

Notes / preliminary analysis

localizeLabels uses the SDK's client-side helper (StyleManager.localizeLabels on iOS, the
maps-localization extension on Android). It rewrites ["get", "name_xx"] in symbol layers'
text-field, so:

• it only supports the 13 languages that have name_* fields in Mapbox Streets v8
  (ar de en es fr it ja ko pt ru vi zh-Hans zh-Hant); the list is hard-coded in both SDKs;
• it only sees top-level layers, so it does nothing on Standard, whose labels live in the
  basemap style import. On Android the helper even throws there:
  "Mapbox Standard style does not support client-side runtime localization. Consider using
  Mapbox internationalization capability instead" (see [Bug]: Android Crash when using the standard mapbox style #4095).

Mapbox's recommended way is the settings service: MapboxCommonSettings.language /
MapboxCommonSettings.worldview. Tiles are then requested already localized for any supported
language, on any style. This is already available in the SDK version we use (11.23.1).

Proposal: keep the localizeLabels prop API unchanged. Without layerIds, set the language
through the settings service. With layerIds, keep using the client-side helper as today.
Notes from prototyping:

• the map engine reads this key from the persistent settings storage;
• the setting is app-wide, so with several maps the last one set wins;
• runtime switching works without reloading the style.

I have a working implementation tested on iOS and Android and can open a PR.

Additional links and references

No response