# generaltranslation: General Translation Core SDK: isSameDialect
URL: https://generaltranslation.com/en-GB/docs/core/functions/locales/is-same-dialect.mdx
---
title: isSameDialect
description: API reference for the isSameDialect function
---

## Overview

The `isSameDialect` function checks whether multiple BCP-47 locale codes represent the same dialect without requiring a GT class instance.

***

## Reference

### Parameters

<TypeTable
  type={{
  "...locales": {
    type: '(string | string[])[]',
    optional: false,
  }
}}
/>

### Returns

`boolean` - `true` if all locale codes represent the same dialect

***

## Examples

```typescript
import { isSameDialect } from 'generaltranslation';

// Same dialect checks
console.log(isSameDialect('en-US', 'en-US')); // true
console.log(isSameDialect('en', 'en-US')); // true (base language matches regional)
console.log(isSameDialect('en-US', 'en-GB')); // false (different regions)
console.log(isSameDialect('en-US', 'es-ES')); // false (different languages)
```

***


## Notes

* Considers base languages as parents of regional variants
* Regional variants must match exactly
* Essential for locale fallback logic
* Accepts flexible input formats
* No external dependencies

## Next steps

* Use GT class method [`isSameDialect`](/docs/core/class/methods/locales/is-same-dialect)
* Compare languages with [`isSameLanguage`](/docs/core/functions/locales/is-same-language)