WHY is 'Gabrielle' pretending to be French???!!!

I took it as a reference to Meryl Streep's fake (Polish) accent in Sophie's Choice. The protagonist in that film is also named Nathan.

I personally think that Gabrielle is a representation of both Nathan's primal instincts that he feels the need to suppress, and what he believes to be what he needs as a spouse. She is the acceptable, sexy, subservient female counterpart that he wants. She's not covered in body hair or self conscious and ashamed, i.e. human. But therein lies the truth of the film. She is a lie. She has manipulated him into thinking he has found what he wants, when in reality she is no more real than the freak he turned Lila into. There's a reason the film is titled "Human Nature" and it's not just because they teach an ape-man how to speak. All the characters either fight their natural instincts and are miserable or give in to their primal urges and are cast out. Because society, man.