| Sg | Pl | |
| Nom | orrosta | orrostur (rule) |
| Acc | orrostu (rule) | orrostur (rule) |
| Dat | orrostu (rule) | orrostum (rule) |
| Gen | orrostu (rule) | orrostna (rule) |
| Sg | Pl | |
| Nom | orrostan (rule) | orrosturnar (rule) |
| Acc | orrostuna (rule) | orrosturnar (rule) |
| Dat | orrostunni (rule) | orrostunum (rule) |
| Gen | orrostunnar (rule) | orrostnanna (rule) |