Multimodal lessons are the cat's meow in ESL so I try to use as many audio texts as possible in my classes. Here are two great compact speaker systems I have found. The Elecom Ball is inexpensive, stylish, light, and battery-free but not very loud.
Audio-technica's battery-powered gadget is a lot more expensive but the sound quality and volume are really incredible for such a slim little body--I want to marry it.
