I've tried getting Festival working with Asterisk.
Here is what debugging from asterisk says:
-- Executing Festival("SIP/VoIP-e576", "please record your
message") in new stack
== Parsing '/usr/local/etc/asterisk/festival.conf': Found
Aug 2 07:14:49 WARNING[49829]: app_festival.c:444 festival_exec: Festival
returned ER
== Spawn extension (mvp-line2, 2101, 1) exited non-zero on
'SIP/VoIP-e576'
And here's the snippit from the festival server:
client(5) Tue Aug 2 07:14:49 2005 : accepted from localhost
SIOD ERROR: unbound variable
tts_textasterisk
client(5) Tue Aug 2 07:14:49 2005 : disconnected
And grep -v ^\; festival.conf
[general]
host=localhost
port=1314
festivalcommand=(tts_textasterisk "%s" 'file)(quit)\n