\setuplayout[grid=yes] \showgrid

% \enabletrackers[streams.flushing]
% \enabletrackers[streams.collecting]

\setuppagenumbering[alternative=doublesided]

\starttext

\enableoutputstream[en]

    \dorecurse {3} {
        Are you sleeping, brother John?\footnote{xxx}
        x \footnote{note \recurselevel}\input tufte \par \pushoutputstream
    }

\enableoutputstream[de]

    \dorecurse {3} {
        Bruder Jakob, schläfst du noch?\footnote{yyy}
        x \footnote{note \recurselevel}\input ward \par \pushoutputstream
    }

\disableoutputstream

\input tufte \page[left]

\synchronizestreams[en,de]

\page \flushoutputstream[en]
\page \flushoutputstream[de]

\stoptext
