Can I change the tempo of a song in Sparkyard to make it slower or faster?

No, this isn't a feature we currently offer in Sparkyard.

The tempo of each song is carefully chosen to suit the age range it's written for, but for rehearsal purposes we understand that it is helpful to teach it a little at a time. Therefore, you can isolate lyric lines in the Words On Screen lyric view by double-clicking on them, which will help the children to learn them quickly and easily.