so you hear with 'English' ears.
Yeah, it's what used to be called the 'phonemic grid' in linguistics, one's primary language (which is not always the first acquired) largely determines how a person perceives sounds and there do seem to be limits on how much distinctions not found in the primary language will be perceptible when they hear or learn other languages.
With English and Polish this means that English speakers will never hear the distinction between sz and ś (or cz and ć etc) that clearly.
Polish speakers will never hear distinctions between 'pet' and 'pat' (especially in the middle of a sentence) that clearly (and they're liable to not hear final p, t or k as pronounced by many Americans at all).
There are also limits on things like how well speakers of non-tonal languages will ever be able to hear tonal distinctions in Chinese or Thai (for example). Polish learners are also generally terrible at long and short vowel distinctions in languages like Japanese where they are crucial
These are normal phenomena that for some reason become the focus of weird political debate here...