I don’t recommend assigning products to language, changing language of a product is not a good idea due to the way the products are linked to language specific categories, tags, attributes etc.
Just create the products in the main language and then hit the plus next to the other languages to create the translation, it is the same as translating a post or page in Polylang.
That option is not supported by definition as explained in the home page and readme of this plug-in.
Woocommerce pages are effectively empty apart from a woocommerce shortcode, we need to know the language first in order to know what content to display and not the other way round