Apparently,[* 1] neither characteristic was present in the preceding Primitive Irish period, though initial mutations likely existed in a non-grammaticalised form in the prehistoric era.
[4][full citation needed] Contemporary Old Irish scholarship is still greatly influenced by the works of a small number of scholars active in the late 19th and early 20th centuries, such as Rudolf Thurneysen (1857–1940) and Osborn Bergin (1873–1950).
Nouns and adjectives are declined in three genders (masculine, feminine, neuter); three numbers (singular, dual, plural); and five cases (nominative, vocative, accusative, dative and genitive).
Fragments of Primitive Irish, mainly personal names, are known from inscriptions on stone written in the Ogham alphabet.
They are represented mainly by shorter or longer glosses on the margins or between the lines of religious Latin manuscripts, most of them preserved in monasteries in Germany, Italy, Switzerland, France and Austria, having been taken there by early Irish missionaries.
Whereas in Ireland, many of the older manuscripts appear to have been worn out through extended and heavy use, their counterparts on the Continent were much less prone to the same risk because once they ceased to be understood, they were rarely consulted.
[6] The earliest Old Irish passages may be the transcripts found in the Cambrai Homily, which is thought to belong to the early 8th century.
Further examples are found at Karlsruhe (Germany), Paris (France), Milan, Florence and Turin (Italy).
A late 9th-century manuscript from the abbey of Reichenau, now in St. Paul in Carinthia (Austria), contains a spell and four Old Irish poems.
In addition to contemporary witnesses, the vast majority of Old Irish texts are attested in manuscripts of a variety of later dates.
(However, most /f fʲ/ sounds actually derive historically from /w/, since /p/ was relatively rare in Old Irish, being a recent import from other languages such as Latin.)
(This is much like the situation in Old English but different from Ancient Greek whose shorter and longer diphthongs were bimoraic and trimoraic, respectively: /ai/ vs.
This special vowel also ran rampant in many words starting with the stressed prefix air- (from Proto-Celtic *ɸare).
2A similar distinction may have existed between /o₁ː/ and /o₂ː/, both written ⟨ó⟩, and stemming respectively from former diphthongs (*eu, *au, *ou) and from compensatory lengthening.
All short vowels may appear in absolutely final position (at the very end of a word) after both broad and slender consonants.
The front vowels /e/ and /i/ are often spelled ⟨ae⟩ and ⟨ai⟩ after broad consonants, which might indicate a retracted pronunciation here, perhaps something like [ɘ] and [ɨ].
All ten possibilities are shown in the following examples: The distribution of short vowels in unstressed syllables, other than when absolutely final, was quite restricted.
The phoneme /u/ tended to occur when the following syllable contained an *ū in Proto-Celtic (for example, dligud /ˈdʲlʲiɣuð/ "law" (dat.)
The occurrence of the two phonemes was generally unrelated to the nature of the corresponding Proto-Celtic vowel, which could be any monophthong: long or short.
Ambiguity in these letters' pronunciations arises when a single consonant follows an l, n, or r.[13] The lenited stops ch, ph, and th become /x/, /f/, and /θ/ respectively.
Geminate consonants appear to have existed since the beginning of the Old Irish period, but they were simplified by the end, as is generally reflected by the spelling.
Eventually, however, ll, mm, nn, rr were repurposed to indicate nonlenited variants of those sounds in certain positions.
Nouns decline for 5 cases: nominative, accusative, genitive, prepositional, vocative; 3 genders: masculine, feminine, neuter; 3 numbers: singular, dual, plural.
Verbs display tense, aspect, mood, voice, and sometimes portmanteau forms through suffixes, or stem vowel changes for the former four.