You can build speakup as modules so it's just a matter of getting the sources from git and then building the modules. It'd be better to use GRML as a host than the LFS live CD as that is unmaintained and GRML already has git and everything else you're going to need. But if you want to use the LFS live CD you can do that too you'll just have to look at the BLFS book for the directions to install git from the sources and then go from there. If you need further assistance just send a note and I'll see what I can do to help.
