"The built-in speaker of the iPad is simply insufficient volume to allow the iPad and AAC software to function as an AAC device. Through the iPad's Bluetooth, which stays active even after sleep/wakeup, my iPad Speaker increases volume about 200%. And it weighs only 3.5 oz (1/4 lb). The rechargeable battery lasts 2-3 days." RJ
The speaker comes with my super-dooper VELCRO® BRAND fastener, for sticking it to the back of your ipad/case.
The speaker is only 1/2" thick so it's quite a low profile and doesn't interfere with movement.