[Mac] Can we do language tagging?

[mcdurdin]

Ideally, we want to list each keyboard separately through the Apple IM UX, rather than the approach we currently take of having Keyman listed as an IM with each keyboard in a submenu under that.

@jahorton wrote:

For iOS: https://developer.apple.com/documentation/uikit/uiinputviewcontroller/1618200-primarylanguage

If Apple's done it for iOS, there's likely something similar for macOS input methods somewhere. Linking it here since the paradigms involved are likely similar.

... but, I'm having a lot of trouble finding anything similar on the macOS end.

Tom wrote:

An IM can definitely be installed as a keyboard for a specific language, as long as it's one of the ones that is predefined in the OS. However, I think it would require a completely separate installation.

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Per https://docs.google.com/document/d/1nQi65m2i9DrAmwG_ahdYtn5JcWYTwI_kJoSLeK2nPAs/edit:

It appears that the list of native languages is fairly limited and not extensible, so there is no way to identify a new language (either in Language & Region, or in Input Methods) by entering a new BCP-47 language tag. Also, I have not yet been able to find any way to install/develop a new input method for an existing language. Keyman for macOS is added as a keyboard under “Multiple Languages”. And it looks like maybe that is the only way. (More research needed…)

This page notes that TISIntendedLanguage is a Plist key that can be used to supply a BCP-47 value to indicate the intended language for a keyboard. Keyman specifies “mul”, which causes the UI to show Multiple Languages.

"However, iOS and OS X only support the language ID syntax consisting of a language designator and optional region or script designator." - https://developer.apple.com/library/content/documentation/MacOSX/Conceptual/BPInternational/LanguageandLocaleIDs/LanguageandLocaleIDs.html

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See also:

• [Mac] RTL does not appear to be triggered in Word 2016 #170
• feat(mac): Keyboard switching hotkeys #1401