polski · A1 · grammar · 4 minutes
Instrumental after być
Use instrumental for professions, roles, and national identity nouns after być.
Understand the choice
Polish distinguishes a role noun from an adjective description. Jest lekarką uses instrumental noun; jest miła uses nominative adjective agreeing with Anna.
Core rule: A predicate noun after być normally takes instrumental: -a→-ą for feminine, many masculine nouns → -em/-iem. Predicate adjectives remain nominative.
Notice it in context
Anna jest lekarką, a Piotr jest nauczycielem.
Anna is a doctor, and Piotr is a teacher.
Lekarką is feminine instrumental; nauczycielem masculine instrumental.
Jestem studentem i jestem zmęczony.
I am a student and I am tired.
Studentem is instrumental role; zmęczony is nominative adjective.
Maria jest Polką, ale jej mąż jest Niemcem.
Maria is Polish, but her husband is German.
Polką and Niemcem are nationality nouns in instrumental.
What to remember
- Simple identification with to often uses nominative: Anna to lekarka.
- Instrumental plural commonly ends -ami: są lekarzami.
Common trap: Do not put an adjective into instrumental just because it follows być.