It seems that Vattel was available in English as early as 1759 and a copy was on hand during the writing of the Constitution.
I believe there was an English version as early as 1759 or 1760, which referred to "the natives or indigenes," but did not use the term "natural-born." As far as I am aware, the only legal treatise using the specific term "natural-born" during that period was
Blackstone, who defined "natural-born" subjects according to
jus soli principles, while recognizing
jus sanguinis had been applied to children born outside the realm under various statutes.
1759
http://hua.umf.maine.edu/Reading_Revolutions/Vattel.html
Isn’t it important to understand how the framers interpreted Natural born Citizen to verify what the words were? Of course anyone could translate from the French and we know how the Chitty version in 1833 translated the natural born section.
Blackstone is writing from an English law perspective correct? So his view point is different from Vattel and from that held by the writers of the Constitution.