Subject: Re: [Slim] Seeking rough consensus for draft-ietf-slim-negotiating-human-language

From: "Doug Ewell" <[email-masked]>
Date: Mon, 16 May 2016 07:39:09 -0700

Gunnar Hellström wrote:

>> What does this have to do with the meaning of 'zxx' as "No linguistic
>> content", or for that matter "Not applicable" (the other Description
>> field currently associated with 'zxx')?
>
> The thought was that the tags are ordered in preference order and
> since there was no preference on the highest level in the example to
> use language contents in text, therefore that preference level is
> marked with "No linguistic content". Not until coming to specifying
> lower preferences, there is a desire to use text for linguistic
> content.

Language tags indicate the language, and variant(s) thereof, of the
content thus tagged. A tag of "zxx" indicates content that is not
linguistic in nature, such as instrumental music or the sound of fingers
snapping, or an origami bird, or the Mona Lisa.

What you are trying to implement is a sentinel that means "Here is a
boundary between items of higher preference or priority, and items of
lower preference or priority." It is a special flag value. It doesn't
mean "no linguistic content."

> I do not realize why this use of 'zxx' is not in line with the
> definition of the use of BCP 47 subtags. Is the intention with 'zxx'
> specified somewhere? The name looked useful for me.

This is from RFC 5646, Section 4.1 ("Choice of Language Tag"), item 5,
bullet point 3:

"The 'zxx' (Non-Linguistic, Not Applicable) primary language subtag
identifies content for which a language classification is inappropriate
or does not apply.  Some examples might include instrumental or
electronic music; sound recordings consisting of nonverbal sounds;
audiovisual materials with no narration, dialog, printed titles, or
subtitles; machine-readable data files consisting of machine languages
or character codes; or programming source code."

Notice the key term here: "content." The line "a=humintlang-send:zxx" in
your example would mean "I prefer to send CONTENT that is non-linguistic
in nature." Perhaps it means that the user prefers to communicate by
whistling or making facial gestures.

> We could put a number for where the preferences for language in one
> medium starts relative to the others. That is however so close to the
> q-number notation that it probably saves more implementation effort to
> use the q-number notation.
>
> The example would then be:
>
> m=video ...
> a=humintlang-send:1;ase
> a=humintlang-recv:1;ase
>
> m=text ...
> a=humintlang-send:3;en
> a=humintlang-recv:3;en
>
> I put here 3 instead of 2 to indicate a clearly lower preference for
> written Ennglish as an alternative.

That is exactly what I meant by "create a mechanism to do that." The
numbers 1 and 3 are clearly defined as an indication of preference. As
you observed, q-numbers would be similar, and might be better because
they are already used and understood in other contexts.

I'm not stating an opinion for or against the additional complexity
here. I do think some of the use cases that have been used to justify
preference mechanisms are excessively elaborate and far-fetched, and
might even dilute the more realistic arguments. My point here is just
that, if SLIM does need a preference mechanism, an imaginative
interpretation of "no linguistic content" isn't it.

> Thanks for watching. Can you explein in some more words why it would
> not be proper to use 'zxx' in a place where the syntax requires a
> language subtag, but we do not have any language content?

See the quote from RFC 5646 above. What you're trying to define is a
boundary between preferences, not an indication of non-language content.

--
Doug Ewell | http://ewellic.org | Thornton, CO 🇺🇸

---

From: "Doug Ewell" <[email-masked]>
Date: Tue, 17 May 2016 07:56:21 -0700

Gunnar Hellström wrote:

>> means "the user prefers to sign in American Sign Language while
>> simultaneously typing non-linguistic text, such as gibberish." I
>> don't think that is what is intended.
>
> No, it means my highest preference is to use video with american sign
> language and have text available for items such as phone numbers,
> dates, web urls, email-addresses etc that is more rapid and reliable
> to type than to sign ( or say ).

Oh, well, you hadn't said that before. If you really are specifying that
you want a text channel to send non-linguistic content, then yes, the
line with "zxx" is appropriate. If you are using it as a placeholder to
help implement a 2-dimensional priorities matrix in one dimension, then
it is not appropriate.

> However, that difference is not essential for our discussion. The mere
> existence of the text media description in sdp is sufficient to
> express that I want to establish text media.  

OK, but remember that the use of 'zxx' by itself doesn't change anything
about the way priorities are expressed. If you had instead sent:

m=text ... 
a=humintlang-send:bsk

and then used the "text in Burushaski" stream to send phone numbers and
dates, the result would be exactly the same.