el bierzo has always been considered a bridge between galicia and leon province; but with salient particular features, which led to defining this speech of el bierzo as bercian dialect in the 19th century, being considered part of the galician linguistic domain by antonio fernández morales in 1861 and part of the leonese linguistic domain by ramón menéndez pidal, the latter stating that the dividing line between leonese and galician should be placed between the basins of the cúa and sil rivers. in 1934, verardo garcía rey gathered the vocabulary of the bercian dialect in the publication: "vocabulario de el bierzo", where the author makes clear that after his fieldwork, he would re-place the dividing line between the asturleonese and the galician-portuguese linguistic groups, setting it strictly along the sil river. jesús garcía y garcía, in 1994, places the mentioned line from the high cúa river up to a place in ponferrada's municipality (dehesas, fuentesnuevas).