Many other languages name the seventh-day a name meaning Sabbath. Doesn’t this prove Saturday is the seventh-day?

Answer: Yahuwah ordained that there would be a distinction between the numbered days of the week and the name “Sabbath,” which he called His holy seventh-day. Sabbath has never been synonymous with Saturday or Sunday. In like manner the word "Sabbado" in Spanish means Sabbath not Saturday.  Spain and Mexico are both countries that have also been influenced by the Roman Catholic Gregorian calendar.  They have simply applied their word for Sabbath the seventh-day exactly as we have within the context of our assumption that the Gregorian calendar is one and the same as that of Scripture.  Nothing can be further from the truth.  It is a Roman tradition that has taken us all unawares.  We have forgotten our history that defines Saturday and Sabbath as two distinct days on two distinctly different calendars.

Sabbath:  The word was never in England, as in some continental countries, a vernacular synonym for “Saturday”, though English writers of mid. Latin used dies Sabbati as frequently as dies Saturni.  The Oxford English Dictionary, page 2613