<BR>I like Tex's approach to description--start with the name and define it in terms of geocoordinates (including a radius; problem is dialect does not disseminate in a completely circular manner & that is a problem indeed here; a visual map, a series of geocoordinates specifying overlapping elipses might be better but of course more complex & this is all getting to be a bit wild . . . too)<BR>
I also agree with Mark Davis that we do need to include altitude, as we have cliff dwellers.<BR>
Finally I note that (as M. Gerard Lang has pointed out) -- these are not time independent; for example when I requested the 16th and 17th century French subtags, I noted that the dialectical variant persisted in the 'Americas' long after all peculiarities (the form 'avoit' instead of the form 'avait' for 'he/she/it had;' the spelling of the past participles with the 'ez' ending instead of a simple 'e' with an accent grave) had been replaced by completely Modern French in France!<BR>
So it's really almost completely impossible to describe dialects, particularly historical ones, independently of time; indeed, I'm thinking that while such a system might be a useful supplement for describing historical variants, it can't at this point at least replace rich physical description of the variant and where it persisted.<BR>
For more modern dialectical variation, this is done all the time with dialect mappings; but alas, with jetliners and such, the dialect map of the U.S. gets quite interesting & my own dialect is strange too (somehow I learned to say 'warsh' for 'wash' the clothes, although I have no relatives from upstate New York; I had a friend I guess).<BR>
But still the dialect mapping is interesting, however much overlapping takes place . . . <BR>
--C. E. Whitehead<BR>
<A href="mailto:email@example.com">firstname.lastname@example.org</A> <BR> <BR>
<H1> </H1><B>Tex Texin</B> <A title="Geocoordinates (was: Re: Proposal to remove Preferred-Value field	for	region YU in LTRU)" href="mailto:email@example.com?Subject=Geocoordinates (was: Re: Proposal to remove Preferred-Value fieldforregion YU in LTRU)&In-Reply-To=F5213263B59D4DBAB2CB3F254401ACB6@DGBP7M81">textexin at xencraft.com </A><BR>Mon Mar 9 06:38:57 CET 2009
</EM><PRE>> You could add a radius around the point... location lat, long, radius 100km.
> A problem with this approach is that as research causes revision of the knowledge of language usage, these tags wouldn't be easily revised.
> Whereas a named entity gets remapped without changing the tag.
> So it might be better to choose a variant name and describe it as language or dialect used at lat, long, radius, etc. and if the understanding of the usage changes, then the definition can be revised.