X is the toughest letter in the English alphabet. I found lots of cool words that begin with the letter X, but the were all Greek to me.(ha ha -no pun intended) Most of the words that begin with X are in fact Greek words. But they don't mean anything to me.
I pick Xylophone because most everyone had one of these musical contraptions when they were young.We were making beautiful music and our parents thought we were attempting to break the sound barrier. OK, so neither one of us were correct.
But I think that when you watch a child play a Xylophone, it is magical. The look on their faces when they first discover that they are making the sounds and changing the sounds. I have yet to see anything but joy on a young child's face as they discover the joy of making music.