Listening to Schumann's Dichterliebe today, I was struck by how similar the song "Das ist ein Flöten und Geigen" is to the Wunderhorn song "Des Antonius von Padua Fischpredigt" and hence also to the Scherzo of M2 (the Scherzo movement came to mind first). Both are in 3/8 time with that dance-like lilt (and with irony), and the spirit of the Schumann song is similar to Mahler's. The last 5 bars of the song and Mahler's song/scherzo are virtually identical - very chromatic but in different keys (the last chord of the Schumann song is D major, Mahler's ends on the low C). Here is the translation to Schumann's song:
There is a fluting and fiddling,
trumpets are blaring within.
There in the wedding circle dances
the best beloved of my heart.
There is a hubbub and a din,
drumming and piping,
and in between are sobbing and wailing
the dear angels.
Then I checked out Mahler's program for the Scherzo:
"When you awaken from that blissful dream and are forced to return to this tangled life of ours, it may easily happen that this surge of life ceaselessly in motion, never resting, never comprehensible, suddenly seems eerie, like the billowing of dancing figures in a brightly lit ballroom that you gaze into from outside in the dark - and from a distance so great that you can no longer hear the music. Then the turning and twisting movement of the couples seems senseless...."
Could Mahler have had Schumann's song in mind when he wrote his song and Scherzo? The ending sounds like a direct quotation to me, and looking at the words of the song and Mahler's program note for the Scherzo, there seems to be a close emotional connection. Anyway, maybe this is already documented somewhere.
BTW, I was listening to Fritz Wunderlich's recording of Dichterliebe - what a voice! It's a shame that he only sang Das Lied. I wish he'd recorded the tenor part in M8 - I think he'd have been fantastic in the "Blicket auf" section....