| Sg | Pl | |
| 1st | ? (rule) | byggjum (rule) |
| 2nd | ?r (rule) | byggið (rule) |
| 3rd | ?r (rule) | byggja (rule) |
| Sg | Pl | |
| 1st | ?a (rule) | ?um (rule) |
| 2nd | ?ir (rule) | ?uð (rule) |
| 3rd | ?i (rule) | ?u (rule) |
| Sg | Pl | |
| 1st | byggjumk (rule) | byggjumk (rule) |
| 2nd | ?sk (rule) | byggizk (rule) |
| 3rd | ?sk (rule) | byggjask (rule) |
| Sg | Pl | |
| 1st | ?umk (rule) | ?umsk (rule) |
| 2nd | ?isk (rule) | ?uzk (rule) |
| 3rd | ?isk (rule) | ?usk (rule) |
| Sg | Pl | |
| 1 | byggja (rule) | byggim (rule) |
| 2 | byggir (rule) | byggið (rule) |
| 3 | byggi (rule) | byggi (rule) |
| Sg | Pl | |
| 1 | ?a (rule) | ?im (rule) |
| 2 | ?ir (rule) | ?ið (rule) |
| 3 | ?i (rule) | ?i (rule) |
| Form | |
| Participle | byggjandi (rule) |
| Past participle | ?r (rule) |
| Middle infinitive | byggjask (rule) |
| Sg | |
| 2nd | byggj (rule) |