Hey Mike!
I'm not an expert in this field so these might not be the right docs.
but the link you gave me only explains how to change your preferred paypal account language, not the checkout language from Woocommerce.
anyway I found someone with the same problem as me here, but with no solution : https://wordpress.org/support/topic/transaltion-of-paypal-payment-page?replies=3
Here's a pic that shows I have an option for Hebrew in the checkout, but English is the default option: http://oi62.tinypic.com/24b84e0.jpg
How can I change my paypal checkout page to Hebrew by default for a guest?