On 2013–08–24 Wolfgang Schuster wrote:

> You missed in the typescript the features setting for the main and also the fallback font.

I did, indeed. However, I'm unsure how to do it (I never needed to
typeset Cyrillic and I can't even tell if it typesets correctly).
The default features should be applied to the regular font and a
special feature set to the fallback font. If I add the
features=default in the font synonym definition, the fallback
breaks. It works, if the star syntax is being used.

I don't quite understand why.

%% not sure which features are required for Cyrillic
\definefontfeature  [cyr-default]      [mode=node, script=cyrl]
\definefontfallback [cyrillic_regular] [name:dejavuserif*cyr-default] [cyrillic]

\starttypescript [serif] [schola]
  %% works
  %% \definefontsynonym [Serif] [name:texgyreschola-regular*default] [fallbacks=cyrillic_regular]

  %% fallback does not work
  \definefontsynonym [Serif] [name:texgyreschola-regular] [features=default, fallbacks=cyrillic_regular]
\stoptypescript

\starttypescript [schola]
  \definetypeface [\typescriptone] [rm] [serif] [schola] [default]
\stoptypescript

\setupbodyfont [schola]

\starttext
  \input knuth

  Традиционная систематика лишайников оказывается во многом условна и
\stoptext

Marco