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title: CLDR Specifications
---

# CLDR Specifications

- [UTS #35: Unicode Locale Data Markup Language (LDML)](https://www.unicode.org/reports/tr35/) is the latest released specification of the CLDR XML format and algorithms, including the interpretation of the CLDR data.
  - [**Development version**](https://www.unicode.org/reports/tr35/proposed.html)
  - [Updating the Spec](/index/cldr-spec/updating-spec)
- [Definitions](/index/cldr-spec/definitions) - common definitions used in CLDR
- [Unicode Locale Extension (‘u’) for BCP 47](/index/bcp47-extension) - an overview of the -u- extension
- [CLDR Survey Tool](/index/survey-tool) - how to use the Survey Tool
- [Coverage Levels](/index/cldr-spec/coverage-levels) - Detailed descriptions of the data required for a language to be considered supported at a specific level
- [Unicode Transliteration Guidelines](/index/cldr-spec/transliteration-guidelines) - how to design and use Unicode transliterators
- [Picking the Right Language Identifier](/index/cldr-spec/picking-the-right-language-code) - how to pick the right language code
- [Collation Guidelines](/index/cldr-spec/collation-guidelines) - how to construct collation rules
- [JSON Bindings for CLDR Data](/index/cldr-spec/cldr-json-bindings)