Declining Foreign Nouns
Polish constantly adopts loanwords for pop culture and technology. Once these words enter Polish, they are declined like native nouns.
For most masculine foreign nouns ending in a pronounced consonant, simply attach standard Polish case endings directly to the word. In the genitive or accusative, you will frequently see the endings -a (often used for brands, awards, people, and living things) or -u (often used for abstract concepts and media forms).
The Apostrophe Rule
Many English loanwords end in a silent vowel (like the unpronounced "e" in YouTube, Google, or remake). When adding a Polish suffix to a word that ends in a silent letter, insert an apostrophe between the foreign word and the Polish ending.
This orthographic rule keeps the original spelling intact while marking the case.
Bringing It Together
Whether a loanword takes an apostrophe depends on its original pronunciation. Facebook (ending in a pronounced consonant) takes a direct ending, while YouTube (ending in a silent vowel) requires an apostrophe.
When combining these in speech, apply the rule that fits each word's phonetics. In this sentence, design takes no ending as a nominative subject, while Google takes the genitive apostrophe form: