\unexpanded\def\startTranslation
{\begingroup
\dosingleempty\dostartTranslation}
\def\dostartTranslation[#1]%
{\iffirstargument
\getrawparameters[Translation][setups=,language=en,#1]%
\fi
\grabbufferdata[Translation][startTranslation][stopTranslation]}
\def\stopTranslation
{\language[\Translationlanguage]%
\Translationsetups
(\,\getbufferdata[Translation]\removeunwantedspaces\,)%
\endgroup}
\starttext
\startTranslation[language=nl]
It betrays a slow-witted mentality to pursue the streams, but not to see the sources of things.
\stopTranslation
\stoptext
Wolfgang