Hi,
I believe that the plain mike icon means that there are lyrics available. And the little dot along with the mike indicates that the lyrics will scroll along with the music to stay in step.
The little dot is actually a clock (which you see when it is enlarged) - to indicate that they keep in time with the music.
Karen
The microphone icon indicates that lyrics are available for this track. If there is a clock with the microphone, that means we have timed lyrics (lyrics can scroll as the song goes along via the Now Playing screen or a Display).