Dear Colleagues,

The following applies equally to Russian and Ukrainian.

Currently "email-ru.tex" c <--> \cyrch. The other strong
candidate is c <--> \cyrc.

The LaTeX notation is not a conclusive argument for
c <--> \cyrc since LaTeX is not an issue for most
Russian/Ukrainian speakers.  More important is
 '{c}--> ts for both the US Lib Congr transliteration
and the Ukrainian official transliteration.

Currently "email-ru.tex" uses 't <--> \cyrc since the
closest English sound is ts.

Maksym Polyakov now has now noted some other good arguments in
favor of c <--> \cyrc:

 > Concerning \cyrc and \cyrch (in both Rus and
 > Ukr) I would make \cyrc -> c and \cyrch -> 'c. Why?
 > When we (Ukrainians and Russians) spell Latin (not
 > English) alphabet we prononce c \cyrc\cyre (or
 > \cyrc\cyrerev for Russian). In Czech, Slovak (and
 > maybe Polish) c represents the sound \cyrc.

The last argument is new to me and very strong.

Note that the *westward* migration of words
usually supports 't <--> \cyrc='{c}:  

           '{c}ar --> tsar (in English)
           '{c}igan --> tsigane (in French)

whereas the *eastern* migration of words supports
c <--> \cyrc:

           circus (Latin)  --> '{c}irk
           centrum (Latin)  --> '{c}entr

(Unfortunately the exact Roman pronunciation of c
is lost!)

On the other hand, eastern migration
equally supports 't <--> \cyrc='{c}
    
           natio (Latin) --> na'{c}i'a (=nation)
           Platz (German) --> pla'{c}


Any further arguments either way?

Cheers

Laurent S

PS.  Adoption of c <--> \cyrc
will force 'c <--> \cyrch.
Then 't --> \cyrc could be an alternative
as a consolation to westerners.