docs: add guidance on handling different scripts, dialects, and variants in translations https://web.tracklify.com/project/2b7ZVgE5/AdminForth/1271/0SNvyTuu/allow-to-select-languages-for-

Author: ivictbor

adminforth/documentation/docs/tutorial/08-Plugins/10-i18n.md

@@ -572,6 +572,71 @@ import { admin } from '../index';
 }
 ```
 
+## Different scripts (writing systems) / regions / variants / dialects
+
+### Scripts (Writing systems)
+
+For some languages you may want translations in a specific, non-default script (or want the choice to be deterministic).
+
+For example, Serbian (`sr`) is written in both Cyrillic and Latin scripts. If you use only `sr`, an LLM may pick a script inconsistently (or default to Cyrillic). To force a particular script, use `translateLangAsBCP47Code`:
+
+```ts
+translateLangAsBCP47Code: { sr: 'sr-Latn' }
+```
+
+Alternatively, you can or course use the script-tagged BCP47 code directly in `supportedLanguages`:
+
+```diff
+--- supportedLanguages: ['en', 'sr']
++++ supportedLanguages: ['en', 'sr-Latn']
+```
+
+However, in this case `sr-Latn` becomes the language identifier everywhere. For example if you expose language codes to an external app (e.g., in URLs or subdomains), you may end up with URLs like `https://my.site/sr-Latn/my-page`, which is sometimes undesirable. You can work around this by remapping `sr-Latn ↔ sr` in the external system, but we generally recommend `translateLangAsBCP47Code` as the dedicated, internal way to keep a clean ISO 639-1 code while translating as a specific BCP47 tag.
+
+If you want to support both scripts explicitly, include both in `supportedLanguages`:
+
+```ts
+supportedLanguages: ['en', 'sr-Latn', 'sr-Cyrl']
+```
+
+### Dialects and national standards
+
+European Portuguese and Brazilian Portuguese differ, so it’s common to use BCP47 region subtags to distinguish them.
+
+To support both:
+
+```ts
+supportedLanguages: ['en', 'pt-BR', 'pt-PT']
+```
+
+If you only want one version (e.g. Brazilian Portuguese) but still want to keep a clean `pt` code in your API/URLs, use `translateLangAsBCP47Code`:
+
+```ts
+supportedLanguages: ['en', 'pt']
+translateLangAsBCP47Code: { pt: 'pt-BR' }
+```
+
+LLM adapters generally understand the BCP47 tags you provide.
+
+### Variants
+
+More rarely, you may need a specific language variant. For example, British English typically uses standard BrE spelling, but the Oxford English Dictionary variant (OED) differs in some cases:
+
+| Standard BrE | Oxford (OED) |
+| --- | --- |
+| colour | colour |
+| organise | organize |
+| realise | realize |
+
+You can use `translateLangAsBCP47Code` to request a specific variant:
+
+```ts
+supportedLanguages: ['en']
+translateLangAsBCP47Code: { en: 'en-GB-oed' }
+```
+
+As any BCP47 tag it is also supported in `supportedLanguages` directly, but again this will make the full tag (e.g., `en-GB-oed`) appear in your API/URLs external systems unless you remap it externally.
+
 ## Translating external application
 
 You can use this module not only to translate admin area of your application but also to translate other parts like SEO-facing or user-facing services.