You don’t have add a new language because8. Dezember 2015 um 16:22
Thank you, this is really nice. Didn’t know \directsetup (i.e. I can’t handle these setups at all).
I also tried to get rid of the bigger space after stops:
\installlanguage[packed][en]
\setuplanguage[packed][spacing=packed]
you can use here (the grouping isn’t necessary)\startsetups[tightspace]
\spaceskip 0.7\interwordspace plus .5\interwordstretch minus \interwordshrink
\stopsetups
\definedescription[BibItem][
before={\directsetup{tightspace}\bgroup\language[packed]},
after={\egroup},
]