The version I learned is in a mixture of probably-mispronounced German and English. Looking at this, I think it's supposed to be kann, not vann. It goes:
I am the German condor, I come from Stivenland. (girls repeat)
Ich vann spiela, (repeat)
on my viola. (repeat)
Vio-vio-vio-la, vio-la, vio-la, vio-vio-vio-la, vio-vio-la.

Then repeat the verse, but say "piana" instead of "viola", and go Plinka-plinka-plinka-plink, plinka-plink, plinka-plink, plinka-plinka-plinka-plink, plinka-plinka-plink,oh (breath), vio-vio-vio-la, vio-la, vio-la, vio-vio-vio-la, vio-vio-la.

Each time the verse is repeated, a new instrument is added onto the beginning of the instrument part:
tuba: umpa-umpa, um-pa-pa
commercial: soapy-soapy-soapy suds, soapy-soapy-soapy suds, soapy-soapy-soapy suds, soapy soapy suds

The final time, the insturment is "on my orchestra", and everyone just sings their favorite instrument.