The text is about how the brain works and, in particular, how different areas of the brain perform different functions. It describes a patient who had damage to one part of the brain. This affected his ability to talk, but not his ability to understand. So, the missing words are: understood spoken language.

SCRIPTS

We learn most about ourselves and the way we function, both physically and mentally, when things go wrong. For a long time, it was thought that the brain acted as a whole in governing the body's functions. Then, in 1861, Paul Broca, a French anatomist and anthropologist, discovered that different parts of the brain perform different functions. After carrying out a postmortem examination on a patient who had had a severe speech impediment, he discovered, as he had expected, damage to a section of the left frontal lobe of the brain. The left side of the brain governs language ability. The patient's problem had been that he could only utter one syllable, though he fully [BEEP].