The Ontology of Accents

Last night at dinner with the department, a colleague, whose native language is not English, declared that he has an accent. Someone else said that he didn't because there was no discernible difference between the way he pronounced words and the way everyone else at the table did. He insisted that this was irrelevant and that he did, in fact, have a different accent than the rest of us because of his native language.

His claim was that an accent is a property. It is something a person has or does not have, or that everyone has an may be classified according to original dialect. The objection is that an accent is really a relation, a non-identity relation in which one's pronunciation is determined to be distinct from others, that is, you can only be said to have an accent relative to some other set of pronunciations taken as the local benchmark from which yours differs.

So, is "having an accent" a property or a relation? Can you have an accent and the people around you not notice or is the accent exactly the noticing of the difference?