How to change sub-items below Music menu

I'm quite new to XBMC but experienced with other products like NPVR. I'd like to change one of the sub-menu items on the home screen below "Music" to Playlists (so maybe swap "Files" for "Playlists"). Is this possible by modifying the skin XML's and if so, can somebody point me in the right direction please.

I'm using the default (and only) skin with Frodo.

Thanks