1  #!/bin/bash
2  pico2wave -l=de-DE -w=/tmp/test.wav "$(cat ${1})"
3  avplay -f wav -loglevel 0 >/dev/null -x 100 -y 50  -vn -autoexit /tmp/test.wav
4  rm /tmp/test.wav

svox.sh TEXTFILE.txt

avplay -f wav -loglevel 0 >/dev/null -x 100 -y 50  -vn -autoexit -filter:a "atempo=2.0" /tmp/test.wav

avplay -f wav -x 100 -y 50  -vn -autoexit -filter:a "atempo=2.0" test.wav

[...]
Failed to set value 'atempo=2.0' for option 'filter:a': Option not found