No support for xx-xx style locale codes (en-US, zh-TW etc.)

I discovered this issue when I was playing around with langswitcher plugin. I noticed that xx-xx style locales doesn't show up on front-end and after further investigation in this topic @rhukster pointed me to this:

Grav\Common\Languages\LanguageCodes::getNames() only knows how to lookup xx style language codes. This would have to be improved to support xx-xx styles too.

https://github.com/getgrav/grav/blob/develop/system/src/Grav/Common/Language/LanguageCodes.php

Here are the most common locales, widely supported by systems and platforms out there:

Description	Locale code
English (American)	en-US
English (British)	en-GB
English (Australian)	en-AU
English (Canadian)	en-CA
French (Canadian)	fr-CA
Chinese (Simplified, PRC)	zh-CN
Chinese (Simplified, Singapore)	zh-SG
Chinese (Traditional, Taiwan)	zh-TW
Chinese (Traditional, Hong Kong S.A.R.)	zh-HK
Chinese (Traditional, Macao S.A.R.)	zh-MO

[rhukster]

I need to find a list of all ISO 639-1 (xx) and 639-2 (xxx) but with an appropriate native language name.

Then I also need to cross correlate this with a list of locale-based names (en-GB, en-US, zh-CN, zh-TW, etc) but these need to have appropriate native names too.

This is not easy to find!

Links to info I've found far:

https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes
https://www.loc.gov/standards/iso639-2/php/code_list.php
http://www.lingoes.net/en/translator/langcode.htm
https://msdn.microsoft.com/en-us/library/ee825488(v=cs.20).aspx

So far i've been able to find resources to ISO 639-1 and 639-2, but nothing to locale-based names with native languages.

[rhukster]

Ok this is closest so far:

https://github.com/jlongster/php-product-details/blob/master/localeDetails.class.php

[rhukster]

and two more:

https://chronoplexsoftware.com/myfamilytree/localisation/languagecodes.htm
http://l10n.mozilla-community.org/~pascalc/localenames/

[rhukster]

I've released an update for this plugin that causes the languages to be displayed with suffix in parens:

English (gb) English (us) English 

This is not the final solution. A proper update to the array with more local languages is the ideal solution, but this will at least work for the time being.

[rhukster]

Fixed for next Grav release: d7f286f

@rhukster could you also add support for zh-TW & zh-CN in next release?

[rhukster]

Already there:

https://github.com/getgrav/grav/blob/develop/system/src/Grav/Common/Language/LanguageCodes.php#L137-L138

[manuel-84]

Hi @rhukster , is it possible to add custom languages not defined into LanguageCodes.php without editing the core?