Emphasis in Polish is one of the easiest topics. But many people make mistakes here too. This may be due to the fact that in their native language a similar word has the last stressed syllable, for example, but in Polish it does not. Is it such a big problem to say a word but put the wrong accent, but you will still be understood? It's up to you.
But here's a story from life. One of our acquaintances went to a cafe at lunchtime. He ordered soup and decided to drink compote. He asked the waitress to bring the drink, but the girl didn't understand him. She did not know what "ka-m-pot" was. She asked again, clarified... It was only after the waitress had explained that she realised that our acquaintance needed "kompot".
Speech errors are often made because of ignorance of the rule and exceptions.
So, in Polish, the stress is constant and falls on the penultimate syllable.
The digressions are few and easy to remember.
The first exception.
Words with atypical stress include the forms of numerals ending in -sta и -set (that is, denoting hundreds). For example, czterysta, siedemset, dziewięćset.
Second exception.
In some loan words, often ending in a -ika or -yka. In this case, the stress falls on the third syllable from the end. For example, logika, statystyka, gramatyka. You can also find atypical stress in other words of foreign origin (but not in all of them), e.g. uniwersytet, ocean, polemika, analiza.
Third exception.
Many abbreviations, especially those consisting of consonants, have the stress on the last syllable. For example, PKP (Polskie Koleje Państwowe), USA.
Fourth exception.
Words with prefixes also have the stress on the last syllable arcy-, wice-, eks-. When the prefix comes before a one-syllable word, e.g. arcyłotr, eksmąż, wicemistrz.
Fifth Exception.
Some verb forms, such as the first and second person plural past tense forms (e.g., chodziliśmy, chodziłyście). The forms of all three singular persons and the third person plural forms of the subjunctive mood are stressed on the third syllable from the end (e.g. robiłbym, robiłabyś). Also the first and second person plural forms of the subjunctive mood have the main stress on the fourth syllable from the end (e.g. robilibyśmy, robiłybyście).
Note, the stressed syllable is pronounced with more force, but the unstressed syllables in Polish should also be pronounced clearly.
Finally, we note that most Poles stress the penultimate syllable in the above exceptions. And this is no longer perceived as a mistake, but is treated as a form acceptable in colloquial speech.
