about 方言,

1. a language somebody is using
and/or
2. a language nobody knows

concerning group 1, clear,
concerning group 2, it is possible like the case involved with BaLan,
he acted as an interpreter to himself, from 'ahh-o-ahh' into 'U-turn',
he also acted as a speaker to Israel, he maybe said 'go to the hell,
Yi3Se4Lie4 people', but Israelite heard of 'God be with you, Yi3Se4Lie4 people,
don't be afraid, victory is waiting for you'

therefore,
what I can say now is that
we have nothing at hand to exclude 方言 like group 2,
although
it is obviously everybody is capable to create 方言 like group 2

in fact, as I mentioned before, a group of people (using King James Bible
and calling themselves The Way) taught everybody should speak 方言 and
everybody could speak 方言, a gentleman even taught me HOW to speak 方言,
of course, I can speak that kind of 方言 like they do, the only question to me
is why I should speak that kind of 方言. Thus, that kind of 方言 should not be
classified as group 2.