cu: словѣ́ньскъ / ⰔⰎⰑⰂⰡⰐⰠⰔⰍⰟ has incorrect Cyrillic glyphs
The Church Slavonic language uses different orthographic conventions than other modern Slavic languages. The appropriate script code is Cyrs: Cyrillic (Old Church Slavonic variant), not Cyrl: Cyrillic.
Hirmos Ponomar is a suitable font with an open licence.
Attached is a screenshot of the name in Hirmos Ponomar font set at 16px, in normal case and title case.

References https://en.wikipedia.org/wiki/Church_Slavonic_language https://en.wikipedia.org/wiki/Early_Cyrillic_alphabet http://www.ponomar.net/cu_support.html
Replacing the Cyrillic part's characters may be impossible, because they share code points with the modern Cyrillic letters.
This may be possible if there's a trick to put two glyphs at the same code point to be selected according to the language code. Something like this is done for Serbian with the 'б' character in some fonts, but I'm not sure that it can be easily done here. @santhoshtr, is it possible here?
Thanks for the link to the font, in any case - we'll consider using it in Wikipedia.
Good point.
I believe this can be accomplished with OpenType font features for localized forms (locl), and should just work according to language tags in the web page.
It works for me in current Firefox and Chrome. Some samples are linked from this page: http://hacks.mozilla.org/2010/11/firefox-4-font-feature-support/
A font can also contain alternate glyphs or historical glyphs, which can be selected through CSS3, although this is probably not necessary for Autonym’s goals. http://www.w3.org/TR/css3-fonts/
On Tuesday, December 3, 2013, Amir E. Aharoni wrote:
This may be possible if there's a trick to put two glyphs at the same code point to be selected according to the language code. Something like this is done for Serbian with the 'б' character in some fonts, but I'm not sure that it can be easily done here. @santhoshtrhttps://github.com/santhoshtr, is it possible here?
It is possible to put two glyphs for same unicode point and with a variation selector, but not all platforms respect it. In our context, answer is no, since the font is applied not based on any language code.
not all platforms respect it
I believe that the latest Firefox, Chrome, and MSIE support this on Mac and Windows. Not sure about Safari 7.
In our context, answer is no, since the font is applied not based on any language code.
I don’t understand what “the font is applied based on” means.
A font’s OpenType Localized Forms (‘locl’) tag should work in a supporting browser as long as language is indicated by an HTML lang attribute. Language attributes are present in the Language sidebar, and on www.wikipedia.org. Autonym font should be applied in these places (currently, it is only in the first). So in our context, the answer would be yes.
Language attributes are present in the Language sidebar, and on www.wikipedia.org. Autonym font should be applied in these places (currently, it is only in the first).
Also in List of Wikipedias, btw :)
Similar issue raised at https://github.com/sanskrit-lexicon/PWG/issues/6 unresolved as well. Contacted http://www.irmologion.ru/developer/fontdev4.html