[MUSIC] So semantics are important in the left hemisphere, the dominant hemisphere in the vast majority of us is critical to semantic expression and comprehension of language. But maybe semantics is a little overplayed. In fact, a great deal of what we understand from each other depends on properties beyond the actual words that we use. So property such as body language, facial expression, context. And then also properties of speech such as loudness or timing or pitch. All of this really contributes a great deal to what we understand about the things that somebody is trying to communicate to us. And the examples of this are very plentiful. In the movie world, I would recommend that you watch Les Triplettes de Belleville, and in that movie there is, there are actually two words [FOREIGN] which are only comprehensible to somebody who speaks french. But the entire movie is perfectly comprehensible by context and prosody and body language and action. So we can communicate without words, and we can communicate better with words if we add a property called prosody. So, prosody is Everything that we do to how we speak, all the inflection, the timing, and the loudness. So, everything that makes it something different from a machine reading a piece of text. So, how do we produce prosody, and how do we understand prosody? Well, it turns out that in the right hemisphere, we have a system that mirrors the system for semantic content in the left hemisphere, and so back here where Wernicke's would be in the left hemisphere, we have an area which is critical to comprehension of prosody. And an area up here which is in analogous place to Broca's area, which is critical for production of prosody. You can have lesions in one of the strokes, or brain tumors, or some type of injury to either one of these places. And the semantic content and the semantic understanding of language will be intact but somehow, a person for instance with damage back here won't interact with others as well as they did before because they're not able to read them. They're not able to read their emotional meaning. Understand what I mean, not what I say. And that is in fact how we communicate. What we mean, what we intend, is the emotional content and that is arguably as strongly influenced by the right hemisphere or even more strongly influenced by right hemisphere than it is by the actual words we choose to use. So lesions here can reduce either comprehension or the production reciprocity but in turn that can lead to social problems, problems interacting with others because what is language? Language is the avenue that we have to communicate with others. And so if we can't communicate, if we can't understand others, if we can't read them, and if we can't communicate to them, we end up more socially isolated and more socially, just things are not working, things are not firing on all pistons in the social Arena. So this is a major issue and you can see somebody who just withdraws from a social environment, and you might see this in the elderly, they withdraw, and the things that one should check for are make sure that they're hearing okay. And make sure that they haven't had simply a stroke in one of these comprehension, or in the right hemisphere, in an area that's not producing very obvious aphasia, but is interfering with their ability to use and understand language. Now on this page you'll see a link and it has an excerpt from a friend of mine reciting Jabberwocky. And his recitation of Jabberwocky is filled with prosody, so much so. I mean the Jabberwocky is a poem that doesn't have a whole lot of semantic content anyway, but you can totally understand that the meaning they import, the emotion behind the performance by listening to his animated performance. So what that tells you is that the communication there is dominated by prosody and very minimally influenced by actual language. [MUSIC]
