Effort of old people to control switching language and evaluation in viewing of  modern audio lesson

Ancient linguistics efforts to direct the language replacement phenomena or that which is measureable and has a large scientific value but it extremes were dispersed among many sources. They have different definitions for this phenomena, the number of letters in which the replacement occurs and the reasons of its occurrences. Ancient linguistics has many views towards it. Some of them counted it as a replacement. This research rebids those efforts by a comparison curricular between what has been demonstrated by the ancient linguistics and results of modern voice studies.