I see your logic but no.

Customer: I need an English/French dictionary.
Me: Sure not a problem.

I lead the customer over to the dual language dictionaries

Me: Here you are. There are quite a few to choose from.
Customer: These all say French/English dictionaries. I need an English/French dictionary.
Me: French/English or English/French it doesn't matter they're the same.
Customer: But how can I use a French/English dictionary if I don't already know French?
Me: They all have both French to English definitions and English to French definitions. Otherwise, you'd have to buy two books to make it work.

At least she had some fairly decent logic to lead up to her confusion....