Irish, like all modern Celtic languages, is characterised by its initial consonant mutations.[1] These mutations affect the initial consonant of a word under specific morphological and syntactic conditions. The mutations are an important tool in understanding the relationship between two words and can differentiate various meanings.
Irish, like Scottish Gaelic and Manx, features two initial consonant mutations: lenition (in Irish pronounced as /ˈʃeːvʲuː/) and eclipsis (in Irish pronounced as /ˈʊɾˠuː/) (the alternative names, aspiration for lenition and nasalisation for eclipsis, are also used, but those terms are misleading).
Originally these mutations were phonologically governed external sandhi effects: lenition was caused by a consonant being between two vowels, and eclipsis when a nasal preceded an obstruent, including at the beginning of a word.
Irish also features t-prothesis and h-prothesis, related phenomena which affect vowel-initial words.
See Irish phonology for a discussion of the symbols used on this page.
Lenition as an initial mutation originally stems from the historical allophonic lenition of an intervocalic consonant, both word internally and across word boundaries, i.e if a word ended in a vowel and the next word began with a consonant + a vowel, the consonant lenited.
Today, these former final vowels are usually elided, but the lenition of following consonants remains and has been grammaticised. For example, Proto-Celtic *esyo "his" caused the lenition of a following consonant due to its final vowel and its modern form Irish: a now causes lenition, keeping it distinct from Irish: a "her" and Irish: a "their", which cause h-prothesis and eclipsis respectively.
Lenition caused stops and *m to become fricatives, *s to debuccalise to pronounced as /[h]/, *f to elide, and the liquids *l, *n, *r to split into fortis and lenis variants. Though by the end of the Middle Irish period lenited *m largely lost its nasal quality, lenited *t debuccalised to pronounced as /[h]/, and lenited *d lost its coronal articulation.
Lenition did not only occur word initially, though non-initial lenition was never grammaticised. For example Proto-Celtic *knāmis → Irish, Old (to 900);: cnáim → Irish: cnáimh "bone", and *abalnā → Irish, Old (to 900);: aball → Irish: abhaill "apple tree".
While it is not initially apparent, the prothesis of and stems from historical lenition combined with vowel reduction.
The prosthetic - of vowel initial words is a fossilised fragment of the Proto-Celtic masculine definite article *sindos. Before vowels, the *s of the ending *-os was lenited to pronounced as /[h]/, which (combined with the loss of the *-o-) devoiced the preceding *-d- to *-t.
The prosthetic of initial words is a fossilised fragment of the d of Proto-Celtic nominative feminine definite article *sindā and masculine genitive definite article *sindī. Since they ended in vowels, a following word initial *s was lenited to pronounced as /[h]/ which (combined with the loss of the *-ā, *-ī) devoiced the preceding *-d to *-t.
The prothetic of vowel initial words has two origins, the first being epenthetic to avoid vowel hiatus, and the second being the fossilised remnant of a historic consonant. For example, the *s of Proto-Celtic *esyās "her" was lenited between vowels to pronounced as /[h]/. Overtime *esyās was reduced to Irish: a but the pronounced as /[h]/ remains when it is followed by a vowel initial word but is now written as part of the following word.
Eclipsis originally stems from the historical coalescence of consonant clusters beginning with a nasal, both word internally and across word boundaries, i.e if a word ended in a nasal and the next word began with a stop or labial fricative, they would coalesce.
Today, many of the former final nasals have been elided, but still have an effect on the pronunciation of a following consonant, which has been grammaticised. For example, the Proto-Celtic genitive plural of the definite article *sindoisom has lost its final nasal and been reduced to Irish: na but it now causes the eclipsis of a following consonant or the prothesis of to a vowel.
The cluster reductions involved in eclipsis turned nasal stops followed by a voiced stop into nasal stops, nasal stops followed by a voiceless stop into voiced plosives, nasal stops followed by a voiceless labial fricative into a voiced fricative, and words which have lost there final nasal add an to vowel initial words.
These cluster reduction did not only occur word initially, though non-initial coalescence was never grammaticised. For example, Proto-Celtic *lindos → Irish, Old (to 900);: lind → Irish: linn "pool", and *kʷenkʷe → Irish, Old (to 900);: cóic → Irish: cúig "five".
This table shows the orthographical and phonological effects of lenition, eclipsis, h-prothesis, and t-prothesis. Vowels are represented by and pronounced as //V//. Consonants are broad before and slender before . See also Irish orthography which has a table showing non-initial lenited consonants which elided or vocalised to form diphthongs or long vowels.
| Unmutated | Lenition | Eclipsis | T-Prothesis | H-Prothesis | Meaning | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Spell. | E.G. | Spell. | E.G. | Spell. | E.G. | Spell. | E.G. | Spell. | E.G. | ||||||
| V v | pronounced as //V// | Irish: '''é'''an pronounced as //eːnˠ// | nV n-v | pronounced as //n̪ˠV// pronounced as //n̠ʲV// | Irish: '''n-é'''an pronounced as //n̠ʲeːnˠ// | tV t-v | pronounced as //t̪ˠV// pronounced as //tʲV// | Irish: '''t-é'''an pronounced as //tʲeːnˠ// | hV hv | pronounced as //hV// | Irish: '''hé'''an pronounced as //heːnˠ// | bird | |||
| B b | pronounced as //bˠ// pronounced as //bʲ// | Irish: '''b'''ean pronounced as //bʲanˠ// | Bh bh | pronounced as //w// pronounced as //vʲ// | Irish: '''bh'''ean pronounced as //vʲanˠ// | mB mb | pronounced as //mˠ// pronounced as //mʲ// | Irish: '''mb'''ean pronounced as //mʲanˠ// | woman | ||||||
| C c | pronounced as //k// pronounced as //c// | Irish: '''c'''eann pronounced as //caːn̪ˠ// | Ch ch | pronounced as //x// pronounced as //ç// | Irish: '''ch'''eann pronounced as //çaːn̪ˠ// | gC gc | pronounced as //ɡ// pronounced as //ɟ// | Irish: '''gc'''eann pronounced as //ɟaːn̪ˠ// | head | ||||||
| D d | pronounced as //d̪ˠ// pronounced as //dʲ// | Irish: '''d'''roim pronounced as //d̪ˠɾˠiːmʲ// | Dh dh | pronounced as //ɣ// pronounced as //j// | Irish: '''dh'''roim pronounced as //ɣɾˠiːmʲ// | nD nd | pronounced as //n̪ˠ// pronounced as //n̠ʲ// | Irish: '''nd'''roim pronounced as //n̪ˠɾˠiːmʲ// | back | ||||||
| F f | pronounced as //fˠ// pronounced as //fʲ// | Irish: '''f'''reagra pronounced as //fʲɾʲaɡɾˠə// | Fh fh | ∅ | Irish: '''fh'''reagra pronounced as //ɾʲaɡɾˠə// | bhF bhf | pronounced as //w// pronounced as //vʲ// | Irish: '''bhf'''reagra pronounced as //vʲɾʲaɡɾˠə// | answer | ||||||
| G g | pronounced as //ɡ// pronounced as //ɟ// | Irish: '''g'''lúin pronounced as //gl̪ˠuːnʲ// | Gh gh | pronounced as //ɣ// pronounced as //j// | Irish: '''gh'''lúin pronounced as //ɣl̪ˠuːnʲ// | nG ng | pronounced as //ŋ// pronounced as //ɲ// | Irish: '''ng'''lúin pronounced as //ŋl̪ˠuːnʲ// | knee | ||||||
| L l | pronounced as //l̪ˠ// pronounced as //l̠ʲ// | Irish: '''l'''eanbh pronounced as //l̠ʲanˠəw// | L l |
| Irish: '''l'''eanbh pronounced as //lʲanˠəw// | baby | |||||||||
| M m | pronounced as //mˠ// pronounced as //mʲ// | Irish: '''m'''áthair pronounced as //mˠaːhəɾʲ// | Mh mh | pronounced as //w// pronounced as //vʲ// | Irish: '''mh'''áthair pronounced as //waːhəɾʲ// | mother | |||||||||
| N n | pronounced as //n̪ˠ// pronounced as //n̠ʲ// | Irish: '''n'''aomh pronounced as //n̪ˠiːw// | N n |
| Irish: '''n'''aomh pronounced as //nˠiːw// | saint | |||||||||
| P p | pronounced as //pˠ// pronounced as //pʲ// | Irish: '''p'''eann pronounced as //pʲaːn̪ˠ// | Ph ph | pronounced as //fˠ// pronounced as //fʲ// | Irish: '''ph'''eann pronounced as //fʲaːn̪ˠ// | bP bp | pronounced as //bˠ// pronounced as //bʲ// | Irish: '''bp'''eann pronounced as //bʲaːn̪ˠ// | pen | ||||||
| S s | pronounced as //sˠ// pronounced as //ʃ// | Irish: '''s'''úil pronounced as //sˠuːlʲ// | Sh sh | pronounced as //h// | Irish: '''sh'''úil pronounced as //huːlʲ// | tS ts | pronounced as //t̪ˠ// pronounced as //tʲ// | Irish: '''ts'''úil pronounced as //t̪ˠuːlʲ// | eye | ||||||
| T t | pronounced as //t̪ˠ// pronounced as //tʲ// | Irish: '''t'''each pronounced as //tʲax// | Th th | Irish: '''th'''each pronounced as //hax// | dT dt | pronounced as //d̪ˠ// pronounced as //dʲ// | Irish: '''dt'''each pronounced as //dʲax// | house | |||||||
The definite article triggers the lenition of:
"the woman"
"of the man" e.g., the man's car (car of the man)
+ = : "to the man"
+ = : "from the woman"
+ = : "in the tree"; "in the autumn"
Lenition is blocked when a coronal consonant is preceded by Irish: an.
"the drink", although is feminine nominative singular
"of the house", although is masculine genitive singular
Instead of leniting to pronounced as //h//, after the definite article, pronounced as //sˠ, ʃ// become pronounced as //t̪ˠ, tʲ// (written):
pronounced as //ən̪ˠ t̪ˠuːlʲ// "the eye" (fem. nom. sg.)
pronounced as //ən̪ˠ t̪ˠiːlʲ// "of the world" (masc. gen. sg.)
The possessive pronouns that trigger lenition are "my", "your (sg.)", "his"
These were originally preceded by the particle and often still are in Munster.
Lenition is blocked in these constructions if two coronals are adjacent.
The singular form is used after numbers and is lenited in the following cases:
Constructions of adjective + noun are written as compounds.
In these constructions coronals are lenited even following other
The possessive pronouns that trigger eclipsis are "our", "your (pl.)", "their"
can mean "his", "her" or "their", but these different uses can still be distinguished, since causes lenition when used as "his", causes eclipsis when used as "their", and neither when used as "her" .
The numbers that trigger eclipsis (the noun being in the singular) are:
Before a vowel is written instead of .
The genitive plural article eclipses a following noun:
In western and southern dialects, nouns beginning with a noncoronal consonant are eclipsed after combinations of preposition + article in the singular (except, Irish: don, and, which trigger lenition)
In environments where lenition occurs a vowel initial word remains unchanged:
However, In environments where neither eclipsis nor lenition is expected, an initial vowel may acquire a prothetic consonant. For example, a vowel-initial masculine singular nominative noun requires a (a voiceless coronal plosive) after the definite article:
Additionally, there is the prothetic (a voiceless glottal fricative), which occurs when both the following conditions are met:
Examples of h-prothesis: