Is your son advanced in other areas? Does he ask probing questions about how things work? Is he an avid 'watcher'? Are other family members unusually intelligent, supporting a genetic predisposition to high intelligence? Does he assemble jigsaw puzzles designed for older children easily? What about other building toys like Legos? 'Yes' answers here would support a high-intelligence theory.

The words 'STOP' and 'PAUSE' could easily have been copied from a TV remote control. (Is the RC in all caps? and your son's writing also all caps?) Still, an impressive achievement for a 2-year old, but not the same feat as spelling 'cat' or 'tomato', or even mixing upper and lower case letters. Copying words can be a visual pattern-recognition thing; spelling them is a whole sound-symbol coding exercise -- so very, very different. (My older son started writing letters at age 2, but in his case, it was clearly a visual pattern thing -- simply copying shapes that he knew were somehow important.)

How does your son play with other children? Is he indifferent to, upset by, confused by, or annoyed by other kids? Does he line things up often, and melt down when his lines are disturbed? Is he anxious or upset by changes in routine? Does he have just a few favorite toys, and play with them the same way over and over? Does he repeat words and phrases he's heard on TV? And if he does 'TV talk,' does it sound different from his regular speech? (Inflection, vocabulary, not appropriate to context) Does he use your hand as a 'tool' to get things instead of pointing? How are his language and speech development coming along? Does he mix up pronouns like 'it' 'me' and 'you', or have trouble with 'Wh' questions? Does he seem over- or under-sensitive to certain sounds, smells, tastes, textures, or sensations? Does he have a strong preference for only a few foods (macaroni and cheese, milk, chicken nuggets) and refuse to eat anything else? How are his sleeping patterns?

Problems in these areas suggest you may want to have him evaluated. Very bright children with issues on the autism spectrum (Hyperlexia, Asperger's Syndrome, PDD, High Functioning Autism) could show the types of behaviors you described for your son, but would also tend to have many of the problems described in the paragraph above.

If he's only got 1 or 2 issues from the second set of questions and they're not too severe, then you probably don't have anything to worry about. Just keep an eye on him, and enjoy your obviously bright little boy.