Dyslexia and polyphony
Very similarly to the case with stuttering, I proposed that there might be a positive correlation between the presence of vocal polyphony and a higher prevalence of dyslexia. This idea was another offshoot of the idea of asynchronous shift to the speech of different human populations. Even if you are only interested in the topic of dyslexia, I would still also suggest to read about the similar correlations between polyphony and stuttering referred to in the previous section. For further reading on the topic of dyslexia and polyphony, you can read the following excerpts from my 2006 and 2011 books.