Student or Learner
You jes' shut up now, an' go to sleep, an' you'll be all hunkydory in the mornin'.
They jes' swallowed 'm alive.
It is an abbreviation of just. That usage and other features of your passages are intended to convey that the speaker is using one of a few dialects of AmE. For example the speaker may be very rustic, or perhaps black.
Last edited by emsr2d2; 18-Aug-2013 at 14:32. Reason: Typo correction.