User blog comment:BobTheDoctor27/July 2012 Update/@comment-1233616-20120821133208

Speaking underwater is completely possible as long as you have air in your lungs. The only problem? Bubbles emitted when you speak disort the sound. So you can talk, but you and others won't be able to understand. Which means that, if you had a Mask of Conjuration, you could use it underwater without any problems. You could just name the power and its weakness, and the enemy wouldn't be able to understand you, something which might be an advantage after all.