The program we recommend to use for handling recordings is Audacity. We use it to basically do the following things:
- clean up any background noise from the recordings
- chop recordings up into the right length, so that they have just the bit of audio we want
- amplify the recording to a standard level
Audacity is completely free. See https://www.audacityteam.org/
If you don't already have it, then you can download and install it here: http://audacity.sourceforge.net/
There is a lot of documentation about Audacity online: http://wiki.audacityteam.org/wiki/Audacity_Wiki_Home_Page
The documentation about using Audacity to prepare recordings for Lingopolo: http://lingopolo.com/help/using-audacity