I recently bought this, but then found the comment below on the Ubu website:
On the Ursonate by Kurt Schwitters
A complete authentic recording is still unknown.
Since 1993, a CD containing the complete Ursonate has been distributed as an “Original Performance by Kurt Schwitters” (WERGO, Mainz, WER 6304-2). The authenticity of the recording has been doubted since its release by artists, scholars, and critics due to the manner of the interpretation and the pitch of the speaker’s voice.
Supposedly, as the publisher quotes the artist’s son, Ernst Schwitters, in the accompanying… Read more