Re: [Ltru] font features in CSS

John Cowan wrote:

> Is the repertoire of characters considered part of the typographic
> convention of a language?  Because if so, hardly two languages will
> share the same conventions.

Not in the context of OpenType. The script and language system tags are 
hierarchical, so what the language system tags indicate are 'particular 
typographic conventions for the given script'. The classic case is

	Cyrillic <cyrl>
		Default <dflt>
		Serbian <SRB >

The Serbian lookup set, in this case, would include mappings from 
default Cyrillic glyphs to preferred Serbian forms for certain letters, 
i.e. the Serbian typographic conventions for the Cyrillic script.

As I wrote earlier, the OT language system tags are not necessarily 
linked to individual corresponding natural languages, but may relate to 
more than one natural language, and there are circumstances in which the 
users of one language might wish to invoke the typographic conventions 
of another.

As I wrote in response to a query from John Daggett today regarding the 
latter situation:

	One scenario that comes immediately to mind, and
	I suspect Jonathan could suggest other examples
	from his experience at SIL, is when users of a
	minority language that is not supported explicitly
	in the OTL language system tags of a given font have
	cultural glyph preferences that are shared by language
	users whose language is supported in that font.
	The example I usually use is that of Macedonian
	Cyrillic, whose users may prefer the localised variant
	forms of some characters that are more widely recognised
	as associated with Serbian. There are a lot of fonts
	that have <SRB > language system support, but relatively
	few with explicit <MKD > support. This is because the
	Serbian preference has been quite well documented,*
	while the Macedonian preference has not.

There are many languages and cultures for which the preferred 
typographic conventions are undocumented or, indeed, may be emerging in 
the case of languages recently reduced to writing. In such cases, there 
may be already-supported language systems in fonts that provide 
preferred forms, and enabling access to OT language system tags 
independent of other language tagging would enable users to access these 
forms without requiring updates to their fonts.

Typographic conventions are not limited to language or typical locale 
preferences. Some conventions may be regional, affecting multiple 
languages within a geographic or market area that elsewhere use 
different conventions. In terms of the variant national typographic 
conventions of publishing of classical Greek texts in different parts of 
Europe, it makes sense even to speak in terms of

	Greek <grek>
		French <FRA >
		German <DEU >

i.e. the French and German typographic conventions of use of the Greek 

I have done font development work for consortia of publishers and, 
although the situation has not yet occurred, I can imagine different 
publishers employing variant typographic conventions and, in the context 
of custom fonts, addressing these via custom language system tags. At 
this point, the connection of such tags to natural languages is 
completely severed and such a mechanism would only make sense if 
addressable independently of document language tagging.

John Hudson


Received on Saturday, 31 October 2009 01:39:53 UTC