This guy makes a good point! English is a mix of a meaning based system (like Chinese) and a sound based system. We don’t write “kubid” we write “cupboard”.
All English speakers use the same orthography (with minor differences like color and colour) so we can understand each other written. But spoken is a different story. I have spoken to many people online via google hangout and sometimes people don’t understand my accent.
I also have some problems understanding some accents, like Scottish English. But these problems vanish when we all use a standardised orthography. If we all wrote in a pronunciation based way, it would be much harder to understand each other, as each English speaking place would have its own orthography.