Robert McCrum, William Cran, Robert MacNeil.
The Story of English.
BBC. 1986
rating : 3.5 : worth reading
p13.
The line between accent, dialect
and language is not a sure or a steady one and is often
disputed, even by specialists. Is Scottish English, for instance, a
language or a dialect? The experts find it hard to be certain. It has
been said that "a language is a dialect with an army and a navy",
but my accent often turns out to be your dialect.