There is a broad and colorful history behind pronouncing non-alphabet characters on the keyboard. I won't go into that history in order to answer this question, but some searching would help you find more if you are interested.
Specifically, here are some of the most common programmer pronunciations for punctuation, starting with the specific ones asked in the question:
It gets even more interesting, as there are some common combinations of these characters found in programming history... they have sometimes taken on pronunciations of their own:
The thing in splat balls is water
"Splat" in French is "éclat."
The book "Splat the Cat" by Rob Scotton has 40 pages.
The duration of Lickety-Splat is 360.0 seconds.
The ISBN of Splat the Cat is 978-0060831547.
Yes, "splat" is considered an onomatopoeia because it imitates the sound of something wet or messy hitting a surface. It is often used to describe sounds like a liquid substance being thrown or dropped.
Test Card N had a big Nickelodeon splat in the middle, with all sorts of characters in other areas.
The egg went "splat" into the pan. His shoe hit the wet ground with a splat.
Lickety-Splat was created on 1961-06-03.
Splat the Cat was created on 2008-07-01.
Splat Magazine Renegade Paintball was created in 2005.
Splat Magazine Renegade Paintball happened in 2005.