---
title: "CFStringTokenizerCopyBestStringLanguage(_:_:)"
framework: corefoundation
role: symbol
role_heading: Function
path: "corefoundation/cfstringtokenizercopybeststringlanguage(_:_:)"
---

# CFStringTokenizerCopyBestStringLanguage(_:_:)

Guesses a language of a given string and returns the guess as a BCP 47 string.

## Declaration

```swift
func CFStringTokenizerCopyBestStringLanguage(_ string: CFString!, _ range: CFRange) -> CFString!
```

## Parameters

- `string`: The string to test to identify the language.
- `range`: The range of string to use for the test. If NULL, the first few hundred characters of the string are examined.

## Return Value

Return Value A language in BCP 47 form, or NULL if the language in string could not be identified. Ownership follows the The Create Rule.

## Discussion

Discussion The result is not guaranteed to be accurate. Typically, the function requires 200-400 characters to reliably guess the language of a string. CFStringTokenizer recognizes the following languages: ar (Arabic), bg (Bulgarian), cs (Czech), da (Danish), de (German), el (Greek), en (English), es (Spanish), fi (Finnish), fr (French), he (Hebrew), hr (Croatian), hu (Hungarian), is (Icelandic), it (Italian), ja (Japanese), ko (Korean), nb (Norwegian Bokmål), nl (Dutch), pl (Polish), pt (Portuguese), ro (Romanian), ru (Russian), sk (Slovak), sv (Swedish), th (Thai), tr (Turkish), uk (Ukrainian), zh-Hans (Simplified Chinese), zh-Hant (Traditional Chinese).