To speak or not to speak

As you can imagine, speech is a very important part of our day-to-day lives. Speech is a very complex process that can be affected by many different things. In this blog entry, I will describe a few case studies relating to speech.

First, to discuss Tan. Paul Broca was a researcher that discovered a patient who, for an unknown reason, could only say the word "tan." He could understand whatever Broca said to him, but the only thing he could respond with was "tan." Upon Tan's death, Broca looked at his brain and found a lesion in the left cerebral hemisphere. This finding determined the location of the speech production in the brain, now called Broca's area. Here are two videos showing Broca's aphasia:
Video 1
Video 2
As you can tell from these videos, people suffering from Broca's aphasia can understand conversation but are unable to produce the responses that they would like to. There is a syndrome that is also related to speech called Wernicke's aphasia in which a person's speech is preserved, but they are unable to understand what they're saying. Their speech seems to be mindless rambling, but the patient believes that what they are saying makes sense. Here is a video showing Wernicke's aphasia:
Video
As you can see in this video, the man believes that he is speaking coherently, but only producing nonsense words.
Here is an image showing where Broca's and Wernicke's areas are located in the brain:


The other case study I will discuss in this blog entry is that of Genie. When Genie was discovered, she was a 13 year old girl that had lived her whole life sheltered in one room. Her family severely abused her and rarely, rarely spent time with her. She was never taught to speak, and was often reprimanded when she attempted to. Due to this, she never developed language abilities. Her lack of ability was interesting to linguists and by studying her they made strides in understanding the development of speech in children and the critical period, the idea that learning language is linked to age. She was able to develop some sort of speech, but it is limited at best. She appeared to be incapable of stringing words together to form sentences, even though testing showed that she was highly capable in right-brained activities. Due to her isolated childhood, she was incapable of developing language as normal children do. In 2001, a film was released based on Genie's life; Mockingbird Don't Sing.

Next blog, I'll tell you about two other effects that brain damage can have on a person.