PolylangShow each product once in the POS, in one Polylang language, and pick that language per store with WCPOS Pro.
WPMLShow each product once in the POS, in one WPML language, instead of once per translation.
WP MultilangShow the POS only the products sold in one WP Multilang language, chosen per store with WCPOS Pro.
TranslationsFix a word in the POS, the plugin or these docs in your language: see it on screen, find it on GitHub, and open a pull request.