Help a newbie PLS

Hello - I’m using MAC OS 10.6.8

I am very new to audio editing in general. I have an audio file (itunes) that has background instruments + vocal + occasionally the singer speaks. I am trying to remove the portions of the song where the singer speaks without removing the instruments or the rest of the vocals when he is singing. Is this possible within audacity for a beginner? I have tried using the tutorials - yet cant seem to understand how to isolate the music from the vocals. The left side of the screen says Stero 44100 HZ 32 -bit float. Thanks in advance for any assistance.

See here: http://manual.audacityteam.org/man/Tutorial_-_Vocal_Removal_and_Isolation
Note the first paragraph:
"This page describes techniques which, on some stereo tracks, may allow you to remove or isolate vocals "
Whether removing the vocals is possible depends on the recording - often it is not possible. See the article for details.