Translate Post Comment Form

Hello,

I want to translate the comment form textboxes of the posts. I can’t find those strings in the theme translating section or the strings locator (I’m using Polylang). I can find every other string: buttons, labels, widgets, etc.

How can I make those strings appear in the string locator? I want them to change according the website selected language.

I’m attaching a capture of the form I’m talking about.

Regards