-- The Basque language usually does not have the sound f so the Romanized Basques pronounced the Latin words without that sound which gave origin to the basic and structural vocabulary of the Spanish continuing without that sound, this persistent phonetic limitation is characteristic of the tongues of the hunter gatherer populations. It may be a coincidence but if the other candidate languages for the European Neolithic have this phoneme is a point in favor of which at least this characteristic is inherited from the languages previous to the Neolithic.
--- Although I know that Mr. Sobrinho Simões is a great "goofy" (in addition to being an extraordinary pathologist) I go back to the Douro / Duero River as a genetic frontier: Heir of immemorial times the northern border of the territory of the Lusitanos and its associates was the final stretch of this river and so it continued when it became part of a province of the Roman empire whose administrative (provincial) boundaries continued to be used even in the time of the Arab empire, until they became stronger due to medieval fragmentation. At the beginning of the Christian reconquest the urban populations of this region (including the city of Oporto) due to this being no man's land nearly disappeared for more than a century while the more primitive and quasi-tribal root populations flourished free of the yoke of the cities. With the final Christian victory the administration and the urban populations return coming partly from the north but the rural populations continued to be the same of always although the dialect of the north will prevail. The coastlines are usually a genetic community, as such this border will not be seen near the mouth of the river for the rest it seems to me that Mr. Sobrinho Simões struck the pick in the row.
--- Although I know that Mr. Sobrinho Simões is a great "goofy" (in addition to being an extraordinary pathologist) I go back to the Douro / Duero River as a genetic frontier: Heir of immemorial times the northern border of the territory of the Lusitanos and its associates was the final stretch of this river and so it continued when it became part of a province of the Roman empire whose administrative (provincial) boundaries continued to be used even in the time of the Arab empire, until they became stronger due to medieval fragmentation. At the beginning of the Christian reconquest the urban populations of this region (including the city of Oporto) due to this being no man's land nearly disappeared for more than a century while the more primitive and quasi-tribal root populations flourished free of the yoke of the cities. With the final Christian victory the administration and the urban populations return coming partly from the north but the rural populations continued to be the same of always although the dialect of the north will prevail. The coastlines are usually a genetic community, as such this border will not be seen near the mouth of the river for the rest it seems to me that Mr. Sobrinho Simões struck the pick in the row.