Irregular Nouns
Some very common nouns in Czech are irregular, often because they preserve old dual forms (referring to pairs of body parts).
Body Parts (Oči, Uši, Ruce, Nohy, Kolena)
These words have standard singular forms but irregular plural forms (originally dual).
1. Oko (Eye) & Ucho (Ear)
In the plural, they change gender from Neuter to something that looks like Feminine but behaves uniquely.
| Case | Oči (Eyes) | Uši (Ears) |
|---|---|---|
| Nom | oči | uši |
| Gen | očí | uší |
| Dat | očím | uším |
| Acc | oči | uši |
| Loc | očích | uších |
| Instr | očima | ušima |
Note the instrumental ending -ma!
2. Ruka (Hand/Arm), Noha (Leg/Foot), Koleno (Knee)
| Case | Ruce (Hands) | Nohy (Legs) | Kolena (Knees) |
|---|---|---|---|
| Nom | ruce | nohy | kolena |
| Gen | rukou | nohou | kolen |
| Dat | rukám | nohám | kolenům |
| Acc | ruce | nohy | kolena |
| Loc | rukou / rukách | nohou / nohách | kolenou / kolenech |
| Instr | rukama | nohama | koleny / kolenama |
Again, notice the -ma ending in Instrumental and the -ou ending in Genitive/Locative.
Other Irregular Nouns
Člověk (Human) -> Lidé (People)
The plural of člověk is totally different: lidé (or colloquial lidi).
| Case | Plural (Lidé) |
|---|---|
| Nom | lidé / lidi |
| Gen | lidí |
| Dat | lidem |
| Acc | lidi |
| Loc | lidech |
| Instr | lidmi |
Dítě (Child) -> Děti (Children)
Dítě is Neuter, but Děti behaves like a Feminine noun in the plural.
| Case | Plural (Děti) |
|---|---|
| Nom | děti |
| Gen | dětí |
| Dat | dětem |
| Acc | děti |
| Loc | dětech |
| Instr | dětmi |