It changes what songs it sings and what the abc setting does and I don't know how/why it sawps! (I konw about the slider on the right which selects music, driving and abc modes and the on/off switch)
mad mode 1:
on music mode. phone key 1 plays skip to my loo. and on abc mode the phone keys do the "can you find the number x?" game.
mad mode 2: in music mode key 1 plays london bridge is falling down and on abc mode the phone keys say things like orange triangle.
there are lots of other differences too but these are the easiest to explain.
It is our 2nd one as the first broke and we took it back. the original one only played mode 1. The replacement was on mode 1 for about 2 months after we got it. then it did mode 2 for about 3 months. now we have occasional brief switches to mode 1 with mode 2 most of the time. its driving me NUTS trying to work out whats changing and we don't have the instructions.
I'm probably missing something really really obvious aren't I......