问题
The International Components for Unicode (ICU) is the underlying library that provides localisation features in various programming languages and environments; I approach this from PHP where the intl extension uses ICU for this purpose.
As I understand it, ICU uses Unicode Common Locale Data Repository (CLDR) for identifying ISO 639 language codes.
Language codes are subject to change
The ISO 639 language codes are actively maintained and have been subject to quite substantial changes over the years; see the change-log for ISO 639-3.
If I am aggressively looking to support internationalisation/localisation features, the implementation of ISO 639 and associated standards becomes important to the requirement specification and delivery of my application. Ensuring that my application can at least identify all valid language codes is important for the delivery of relevant content.
How can I Monitor the ISO 639 Implementation in ICU/CLDR?
The most important aspect to this is simply having a traceable source for updates to the ISO 639 data. So that, if a problem is encountered, I know where to look for upcoming releases and change-logs, where to reports bugs, etc.
When using ICU/CLDR how can I monitor and maintain the ISO 639 implementation?
来源：https://stackoverflow.com/questions/36089760/icu-cldr-iso-639-changes-monitoring-maintenance