Appendix:Old Irish suffixless preterite verbs

The Old Irish suffixless preterite originated chiefly in Proto-Indo-European reduplicated perfect forms, though some unreduplicated forms are represented as well.

In the reduplicated suffixless preterite, the initial consonant or consonant cluster of the root is reduplicated with the vowel e, which triggers lenition of the following consonant. For example, the preterite of is  (from ). In some cases, the consonant after the reduplicating syllable may be lenited out of existence, causing compensatory lengthening of the reduplicating vowel, resulting in a form that appears to be an unreduplicated root in which the vowel has been replaced by a long vowel. For example, the preterite of is  (from ), and the preterite of  is  (from ).

In the suffixless á-preterite, there is no reduplication, and the root vowel is replaced by á ; for example, the preterite of is. This á does not have the same origin as the long vowels mentioned in the previous paragraph (as there is no way for a form like to yield ), but it may have the same origin as the ō in the past tense of the Germanic class 6 strong verbs (e.g., ).

A small number of verbs form the preterite stem differently, for example, preterite , with short a. A few verbs inherit their shape directly from Proto-Indo-European, for example, preterite from , and , preterite  from.

The endings of the reduplicated preterite, which are very similar to the endings of the t-preterite, are the same in the absolute and conjunct, except in the passive (which, as always with Old Irish preterite passives, is formed from a different stem). The second person plural happens not to be attested in the absolute, but was presumably identical in form to the conjunct.

See Category:Old Irish suffixless preterite verbs and its subcategories Category:Old Irish reduplicated preterite verbs and Category:Old Irish á preterite verbs for lists of verbs belonging to this class.

Nondeponent endings
A sample verb for this class is. The endings are as follows:

Deponent endings
In deponent verbs, the plural endings are the same as for nondeponent verbs, while the singular endings are -ar in the first and second person and -air in the third person. A sample verb for this class is. The endings are as follows: