From to- + aith- + Proto-Celtic *begeti. *Begeti was soon conflated with bongaid of similar meaning, leading to sporadic exchanges of forms.
do·aithbig (verbal noun taidbech)
| 1st sg. | 2nd sg. | 3rd sg. | 1st pl. | 2nd pl. | 3rd pl. | Passive sg. | Passive pl. | ||
|---|---|---|---|---|---|---|---|---|---|
| Present indicative | Deut. | do·aithbiuch | do·athbongar | ||||||
| Prot. | ·tathbongat | ||||||||
| Imperfect indicative | Deut. | ||||||||
| Prot. | |||||||||
| Preterite | Deut. | ||||||||
| Prot. | |||||||||
| Perfect | Deut. | ||||||||
| Prot. | |||||||||
| Future | Deut. | ||||||||
| Prot. | |||||||||
| Conditional | Deut. | ||||||||
| Prot. | |||||||||
| Present subjunctive | Deut. | to·aithib | do·aithmet | do·aithbestar | |||||
| Prot. | ·taithmis | ||||||||
| Past subjunctive | Deut. | ||||||||
| Prot. | |||||||||
| Imperative | |||||||||
| Verbal noun | taidbech | ||||||||
| Past participle | |||||||||
| Verbal of necessity | taidbecti | ||||||||
| radical | lenition | nasalization |
|---|---|---|
| do·aithbig (pronounced with /h/ in h-prothesis environments) |
unchanged | do·n-aithbig |
Note: Certain mutated forms of some words can never occur in Old Irish.
All possible mutated forms are displayed for convenience.