This guide is based on this article  found at www.linux-gamers.net.
Install the dependencies
For Mumble/Murmur 1.1.0 and greater (including SVN), Qt 4.3 is required. For the 1.0.0 release, Qt 4.2 is sufficient.
Note: Make sure you have sqlite and/ or sqlite3 in your USE flags in /etc/make.conf, if you haven't emerged qt4 with these before, you need to reemerge it.
emerge dev-libs/boost media-libs/speex x11-libs/libXevie x11-libs/qt (See Note)
For Debian / Ubuntu
apt-get install qt4-dev-tools libqt4-dev libspeex1 libspeex-dev libboost-dev libasound2-dev libxevie-dev libxevie1 g++
It's recommended to remove the package qt3-dev-tools if installed.
If you want to use the bleeding edge versions of Mumble, you'll need to use Debian lenny or Ubuntu Gutsy, as they are the only versions supporting Qt 4.3.
Download the source
Get the mumble source
svn co https://mumble.svn.sourceforge.net/svnroot/mumble/trunk mumble cd mumble/
Compile Mumble and Murmur (Mumble server)
qmake main.pro make
For using push to talk, edit /etc/X11/xorg.conf:
Section "Extensions" Option "XEVIE" "Enable" EndSection
Restart the Xserver.
For text-to-speech voices you will need to install festival and at least a voice. Most distros ship packages for that in their repositories.
cd release/ ./mumble
- see Running Murmur