[Freeswitch-users] Change language of voice conference announcements to different language

[flow27 at meta-matrix.de]

Hello,

I try to make the pre-recorded voice conference announcements available 
in English as well as in German. From an old howto I found a few steps. 
I downloaded the German sound file and extracted it into 
freeswitch/sounds/de/at/ute/... then I made this adjustment to 
freeswitch/conf/lang/de/de.xml:

<include>
   <language name="de" say-module="de" 
sound-prefix="$${sounds_dir}/de/at/ute" tts-engine="cepstral" 
tts-voice="david">
     <phrases>
       <macros>
         <X-PRE-PROCESS cmd="include" data="demo/demo.xml"/>
         <!--voicemail_de_tts is purely implemented with tts, we need a 
files based implementation too -->
         <X-PRE-PROCESS cmd="include" data="vm/tts.xml"/>
       </macros>
     </phrases>
   </language>
</include>


and I made sure the de.xml is included in freeswitch.xml:

   <section name="languages" description="Language Management">
     <X-PRE-PROCESS cmd="include" data="lang/de/*.xml"/>



I was hoping that by setting the default_language parameter:

<action application="set" data="default_language=de"/>

before calling the conference application I could exchange the English 
annoucements with the German ones but this does not work. I read in the 
docs that the default language parameter is mainly for the say-module 
but which parameter then selects the language of the pre-recorded 
announcements?  Is the German say-module even required when I dont want 
to use the say command at all but just want to playback the German 
soundfiles?

In the logfile I see that the language is changed:

83d9e7fc-5212-11e4-a335-2d65638c2a61 Dialplan: 
sofia/external/04124124124 at myprovider.de Action set(default_language=de)

But when the conference starts it is using the English sound prefix:

2014-10-12 15:20:34.503660 [INFO] mod_conference.c:10305 using channel 
sound prefix: /opt/freeswitch/sounds/en/us/callie

How can I change the voice conference annoucement language without 
simply replacing the audio files because I want to have the English 
announcements also available for English-only participants.


Thanks for any help