Audacity is free, open source software for recording and editing sounds.
With Audacity one can record live audio, convert tapes and records into
digital recordings, edit Ogg, MP3, and WAV sound files, and much more.

Audacity requires wxPython or wxGTK and libsndfile, both of which are
available at SlackBuilds.org.   This script builds with support for
libmad, libvorbis, id3tag, and libflac (all of which are included in
stock Slackware), but they can be removed in the "configure" section
of the build script if desired.  Finally, one can also optionally
enable soundtouch or twolame support in the SlackBuild if the
soundtouch or twolame dependencies (available at SBo) have been built
and installed prior to compiling Audacity.  See the Audacity
SlackBuild itself for more information.