Then it would have appeared in regions and dialects with longer and more important contacts with Arabian language.True, but it wouldn't surprise me if an Arabic origin reinforced an existing language-internal development.
More importantly, Andalusian dialect knew a different evolution, preferring to use glottal "h".
An arab influence that appeared in the North, bypassing Andalusia?
(By the way, I made a mistake. It appeared in the XVIIth century, not XVth. Mea culpa.
A that long evolution, absent in outer hispanic speeches as ladino, dosen't strike me as showing an obvious arabian influence.)
Didn't the existance of personal infinitive predate the XVth century?The craziest idea I've heard along those lines is that the Galician-Portuguese personal infinitive developed under Hebrew influence