Interpreting t-h0- mechanism

[Matthew Stuckwisch via CLDR-Users]

>> 1. What is the difference between 'en-t-es-h0-hybrid' and 'en-t-h0-es'?  Both styles are given as example encodings for what would be Spanglish (Spanish-English hybrid), but surely there ought to be a difference
>> 
> The latter style is illegal. The key h0 only currently takes one possible value, h0-hybrid. 
> 
> https://unicode.org/reports/tr35/tr35.html#Hybrid_Locale
> 
> If you are seeing "h0-es" someplace in the spec, please let us know, since that would be a typo.

Indeed, in the documentation it says "Thus Hinglish should be represented as hi-t-h0-en where Hindi is the scaffold, and as en-t-h0-hi where English is", but the table represents the two Hinglishes as hi-t-en-h0-hybrid or en-t-hi-h0-hybrid, which is the source of the initial confusion.  

When it said, "Should there ever be strong need for hybrids of more than two languages or for other purposes such as hybrid languages as the source of translated content, additional structure could be added." it was not clear to me that this meant "it is currently not possible to do this" over "by adding in additional structure [e.g. -h0- tags]".

I work occasionally with documents in Eonaviego which would best be coded as ast-t-gl-h0-hybrid, but then when translated to-from (which there are quite a few to/from Asturian or Spanish), there would be no valid encoding, so being able to represent a hybrid language as a source/destination of a transform is not a pure hypothetical for me.

I will go ahead and file some tickets about the docs/support, thanks

Matéu