I'm sorry but it doesn't sound like my 4 year old, who does have Sotos. The main differences are that my child stopped excessive drooling at around 2 or early 3's and there is no way she could learn to read yet. She does say her abc's sometimes, but sometimes gets confused with them.
It sounds like your child is similar to Sotos, but the best way to rule out or confirm Sotos is to have the NSD1 gene test. Some people will tell you it isn't accurate, but the Dr.'s who wrote the book on Sotos so to speak both agree that the test is almost positively accurate.
Sarah