To set a different system language do as follows:

• Login to the system administration
• Navigate to 'Settings: Protocols: SIP'
• Set 'Language'='de' ('de' - German for example)
• Login to the system shell as a root user
• Navigate to 'sounds' directory

 cd /opt/pbxware/pw/var/lib/asterisk/sounds

• Create the necessary directories

 mkdir de
 mkdir de/digits
 mkdir de/letters

• Find German sound files on the web and upload the files into the created directories
• Restart pbxware service

 /opt/pbxware/sh/stop
 /opt/pbxware/sh/start

NOTE: If a sound file is not found in the new folder, the default sound in English will be played back.