This is the 12586th most frequent Polish word.
nastolatkami
The Polish word "nastolatkami" means "teenagers" (instrumental plural form).
The word 'nastolatkami' here is an instrumental plural form used to indicate the persons with whom the action of speaking occurred.
Rozmawiałem dzisiaj z nastolatkami o ich ulubionych książkach.
Today, I talked with teenagers about their favorite books.
The related word 'nastolatków' is in the genitive plural form, as it complements a noun that implies quantity.
W parku spotkałem grupę wesołych nastolatków.
In the park, I met a group of cheerful teenagers.
The associated word 'nastolatków' functions in the genitive case, indicating possession or relation.