To be a vanjebber is not only to talk shit but to converse in a low way. People from Jebber are considered to be particularly ignorant, uneducated and of low intellect, and are very often lacivious.
Their speech relects this inherent lack of intellect, education and morals.
To spout garbage in a manic irrational manner. To gabble.
'She did nothing but Vanjebber all night
'Look at that Vanjebber talking shit again'