In article , Jack Twilley
writes:

I can understand why Novice and Technician Plus required five words
per minute -- the treaty and all -- but why did General require
thirteen words per minute and Amateur Extra twenty words per minute?

Is there a real reason?

12 to 13 wpm is generally agreed to be above the speed where things such as
"counting dits" work for most people. It's the beginning of the skills which
take one to higher speeds

20 wpm derives from the old 1923-24 "Amateur Extra First Class" which chose 20
as double the old 10 wpm standard. It was reintroduced in 1951 when the current
Amateur Extra class was created.

Both speeds are far below those required of experienced professional Morse
operators.

73 de Jim, N2EY