That is definitely a translatable string and I can see it within events-calendar-pro/lang/tribe-events-calendar-pro-pl_PL.po … however, the translated string is simply ‘Week’. We can definitely change it (can you confirm what the correct translation would be? Is it tydzień?) and you could do this yourself as an interim measure though please be aware you would need to recompile the corresponding .mo file.
Yes, it was in PRO. I tried to find it in ‘the-events-calendar’ files. My mistakes. Thanks.
There are few mistakes in Your translation. I can send You po file via mail if You want.
That would definitely be appreciated, we’re always more than happy to improve the translations. Please do feel free to share your .po file by sharing a download link to it or even email my colleague Leah (who collates translations) directly at pro [at] tri [dot] be.