[bdchauvette]

> 2. Paper and pen (the surfer example) also have technological constraints. It's a "2D" surface, width of line, etc.

This is true, but it's kind of true in the same way that walking and flying both have movement constraints. Flying certainly has limitations, but just like pen & paper give you more flexibility in composition than entering a string of characters, flying offers much more freedom of movement than walking.

> 4. What about non-alphabetic written languages?

Most (all?) current non-alphabetic orthographies are non-pictographic. While many characters for common words may have started that way, the majority of characters in these systems are nowadays not obvious pictorial representations of their meaning.

It's possible that this will eventually be the case with emoji, too, but currently it's not.