Mercii, þat beeþ men of myddel Engelond[,] vnderstondeþ bettre þe side langages, norþerne and souþerne, þan norþerne and souþerne vnderstondeþ eiþer oþer. [John of Trevisa, translation of Bartholomew de Glanville's "De proprietatibus rerum," 1398]Language barrier attested from 1933.
In oþir inglis was it drawin, And turnid ic haue it til ur awin Language of the norþin lede, Þat can na noþir inglis rede. ["Cursor Mundi," early 14c.]