Dyslecsia / Dyslexia
According to an article I came across today, dyslexic children tend to it easier to read and write Welsh, with its regular and consistent spelling system, then English, with its somewhat eccentric orthography. Similarly, few children have problems spelling other regular languages like Italian and Spanish.
However dyslexic children who start by learning Welsh, then later learn English tend to find English spelling very challenging and often use Welsh-style spelling when writing English.
Here are some examples of English spelled with Welsh phonetics:
Ddy cwic brawn ffocs jymps owfer ddy leisi dog.
The quick brown fox jumps over the lazy dog.
Tw bi o not tw bi: ddat is ddy cwestiyn.
To be or not to be: that is the question.
The article also mentions that dyslexic children tend to have more trouble getting to grips with Welsh grammar than with English grammar.