She was missing a chunk of her brain – it didn’t matter
I would be very cautious here. There are many stories about how miraculously people function after brain damage or with half a brain but when examined more closely it turns out there are deficits, just not a super obvious one like inability to speak. Some of Oliver Saks&#x27; cases in The Man Who Mistook His Wife for a Hat demonstrate how functionally people can adapt to the point that others may not notice.<p>In many of these cases there are various skills and modes of perception impacted. Artistic talent, abstract visualization, etc. Proprioception, visual perception (not just acuity but things like recognizing abstract shapes vs &quot;gnosis&quot; of objects). Impulse control. Emotional regulation. Many different kinds of memory.<p>Even the oft-told story about Phineas Gage is mostly false. He had serious metal problems for the remainder of his life, including very poor impulse control. Was it a miracle he survived? Yes. Did he made a full and complete recovery? Absolutely not.<p>I would also be careful about correlating brain volume with complexity. We know volume doesn&#x27;t correlate with intelligence between species. Whales are not more intelligent than humans despite having larger brains... their brains are just less densely packed. So being born with a brain that is &quot;too small&quot; can be less of a deficit than you might expect in some cases if the brain matter that is present is of higher complexity - though keep in mind most babies born with smaller than expected brains have profound and permanent disabilities so any contrary cases are very rare exceptions.