Does this occur on every pages? Or only some specific pages?
Yes on every pages.
Did you make the test wiith only WooCommerce + Polylang and no other plugins? I suppose thatt you are using another plugin to make Polylang and WooCommerce work together. Did you deactivate this plugin too?
Yes i have tried with only Woocomerce ( 3.1.2 ) + Polylang (2.2 ) and no other plugin
Could you install the plugin Query Monitor and check if you detect a very long database query?
Yes i have installed the plugin.
Results:
polylang + woocommerce – / 10,07s / 22646kb / 0,0276s / 51Q
polylang – / 0,43s / 12495kb / 0.0147s / 41 Q
woocomerce – / 0,54s / 17577ks / 0,0544s / 41 Q
i have also tried twentyseventeen theme similar results on every page.