Editing Old Irish (section)

==Notable characteristics==
Notable characteristics of Old Irish compared with other old [[Indo-European languages]], are:
* Initial mutations, including lenition, nasalisation and aspiration/gemination.
* A complex system of verbal allomorphy.<ref>{{Cite web|url=http://mvtabilitie.blogspot.com/2008/09/also-known-as-most-demanding.html|title=THE CANTOS OF MVTABILITIE: The Old Irish Verbal System|last=Bo|date=2008-09-27|website=THE CANTOS OF MVTABILITIE|access-date=2018-10-25|archive-date=25 October 2018|archive-url=https://web.archive.org/web/20181025190100/http://mvtabilitie.blogspot.com/2008/09/also-known-as-most-demanding.html|url-status=live}}</ref>{{self-published source|date=July 2024}}
* A system of ''conjugated prepositions'' that is unusual in Indo-European languages but common to Celtic languages. There is a great deal of allomorphy here, as well.
* Infixed or prefixed object prepositions, which are inserted between the verb stem and its initial prefix(es). If a verb lacks any such prefixes, a dummy prefix is normally added.
* Special verbal conjugations are used to signal the beginning of a [[relative clause]].

Old Irish also preserves most aspects of the complicated [[Proto-Indo-European language|Proto-Indo-European]] (PIE) system of morphology. Nouns and adjectives are [[declension|declined]] in three genders (masculine, feminine, neuter); three numbers (singular, dual, plural); and five cases (nominative, vocative, accusative, dative and genitive). Most [[Proto-Indo-European nouns|PIE noun stem classes]] are maintained (''o''-, ''yo''-, ''ā''-, ''yā''-, ''i''-, ''u''-, ''r''-, ''n''-, ''s''-, and consonant stems). Most of the complexities of [[Proto-Indo-European verbs|PIE verbal conjugation]] are also maintained, and there are new complexities introduced by various [[sound change]]s (see [[#Verbal allomorphy|below]]).