I believe that "accent" here refers to "phonetics of a foreign language applied by a non-native English speaker". i.e. German speakers who merge /w/ and /v/ bec

I believe that "accent" here refers to "phonetics of a foreign language applied by a non-native English speaker". i.e. German speakers who merge /w/ and /v/ because no such distinction exists in German. That's a different kind of accent from an American, British or Kiwi accent, etc, which are produced by divergent populations of native English speakers.