Inflection

In Irish, words do not just change by adding endings; the core of the word, or the “stem”, can also change. This is known as internal inflection. These changes, which affect consonants and vowels inside a word, are fundamental to forming plurals, possessives, and different verb tenses. The main types are palatalisation, depalatalisation, syncope, and devoicing.

Palatalisation (An Caolú)

Palatalisation, or caolú (“slenderisation”), is the process where a “broad” consonant becomes a “slender” consonant. In writing, this is usually shown by inserting an i next to the consonant to mark it as slender. This simple spelling change often reflects a shift in pronunciation where the consonant is articulated further forward in the mouth, towards the hard palate.

• bád [bɑːd] (a boat) becomes báid [bɑːdʲ] (of a boat; boats)

Here, the broad d in bád becomes a slender d in báid, indicated by the new i.

Sometimes, making a consonant slender requires more significant changes to the vowels in the stem. The primary goal is always to change the quality of the final consonant, but this can trigger a domino effect on the surrounding vowels to maintain the “slender with slender, broad with broad” spelling rule.

For example, the change from fear (a man) to fir (of a man; men) involves changing the broad r to a slender r. This forces the vowel ea to change to i to keep the spelling consistent.

Some vowel changes are irregular and do not follow the common patterns.

• mac (son) becomes mic, not the expected *maic.
• mall (slow) becomes moille, not *maille.

The ending -ach or -each in multi-syllable words becomes -aigh or -igh through palatalisation.

• báisteach (rain) → báistigh
• bacach (lame person) → bacaigh

However, in single-syllable words, a final -ch is retained, and the vowel before it changes.

• déach (a pair) → déich
• moch (early) → moiche

When Palatalisation is Used

Palatalisation is a key mechanism for forming different grammatical cases and forms:

• Genitive and vocative singular of first declension nouns: an fear (the man) → an fhir (of the man) → a fhir! (man!)
• Weak plural of first declension nouns: an fear (the man) → na fir (the men)
• Genitive singular of second declension nouns (with an -e ending): an lámh (the hand) → na láimhe (of the hand)
• Dative and dual of second declension nouns (in older/formal usage): ar an láimh (on the hand), dhá láimh (two hands)
• Comparative and feminine genitive of first declension adjectives (with an -e ending): fliuch (wet) → fliche (wetter)
• Diminutives with the ending -ín: fear (man) → firín (little man)

Depalatalisation (An Leathnú)

Depalatalisation, or leathnú (“broadening”), is the opposite of palatalisation. It involves changing a slender consonant to its broad equivalent. In writing, this is often as simple as dropping an i that was marking the consonant as slender.

• abhainn (a river) becomes abhann (of rivers)

Here, the slender -nn in abhainn becomes a broad -nn in abhann.

Just like with palatalisation, this process can also require more complex vowel changes, which are often the reverse of the palatalisation patterns.

For example, the change from Éirinn (Ireland) to Éireann (of Ireland) involves changing the slender -nn to a broad -nn, which forces the preceding vowel to change from i to ea.

When Depalatalisation is Used

Depalatalisation is used to form:

• The genitive of third declension nouns: mil (honey) → meala (of honey)
• The genitive of many fifth declension nouns: Éirinn (Ireland) → Éireann (of Ireland)
• The genitive of second declension adjectives: bródúil (proud) → bródúla (of a proud…)
• The form of some verbal nouns: cuir (put) → cur (putting)
• The stem of some multi-syllable verbs before an ending: sábháil (save) → sábhálann (saves)

Syncope (An Coimriú)

Syncope, or coimriú (“shortening”), occurs in words with two or more syllables when an ending is added. It involves dropping the vowel of the stem’s final syllable, effectively merging that syllable with the new ending. This shortens the stem from two syllables to one.

• imir (to play) becomes imríonn (plays)

The stem imir- becomes imr- when the ending -íonn is added.

Syncope happens only when all three of the following conditions are met:

1. The vowel to be dropped is in the last syllable of the stem, and it is short, unstressed, and unaccented (like the second i in imir).
2. This vowel is positioned between a liquid consonant (l, m, n, r) and another consonant.
3. A grammatical ending (for tense, case, or plural) is added to the word.

Syncope can cause several other changes:

• Vowel changes in the first syllable: To obey the “slender with slender” rule, the first syllable’s vowel may need to change.
  • ramhar (fat) → raimhre
  • domhain (deep) → doimhne
• Consonant shortening: The double consonants ll, nn, and rr become single l, n, and r.
  • aoibhinn (delightful) → aoibhne
• Consonant assimilation: Certain consonant combinations are simplified. ln, nl, or dl become ll, while dn or nd become nn.
  • álainn (beautiful) → áille (instead of *áilne)
  • ólann (drinks) → ólla (a form used in verbal adjectives)

• Spreading palatalisation: If the final consonant becomes slender, all adjacent consonants in the new cluster also become slender.
  • bóthar (road) → bóithre (roads)
  • athair (father) → aithreacha (fathers)
• Devoicing: A d can become a t if it follows an s.
  • fearsaid (spindle) → feirste
  • sluasaid (shovel) → sluaiste

When Syncope is Used

Syncope is common in:

• Verbs of the second conjugation ending in -il, -ir, -in, and some in -is.
  • cosain (defend) → cosnaíonn (defends)
  • imir (play) → imríonn (plays)
  • inis (tell) → insíonn (tells)
• Adjective declension, especially for the feminine genitive (-e) and plural (-a, -e).
  • an bhean ramhar (the fat woman) → na mná raimhre (of the fat woman) → na mná ramhra (the fat women)

Devoicing (An Díghlórú)

Devoicing is the process where a voiced consonant (like b, d, g) changes to its voiceless counterpart (p, t, k).

In Irish, this primarily happens to the final consonant of a word stem when it is followed by an ending that begins with an [h] sound. This is different from the automatic final devoicing found in languages like German. A voiced consonant can happily exist at the end of a word in Irish (e.g., scuab [skuəb], póg [poːg]).

The main endings that trigger devoicing are:

• Future/Conditional endings with f- (e.g., -faidh, -fadh), where the f is pronounced [h].
• Verbal adjective/past participle endings with th- (e.g., -tha), where th is pronounced [h].

When a voiced consonant meets this [h] sound, they merge into a single voiceless consonant, and the [h] sound itself disappears. Spelling reforms have sometimes updated the orthography to reflect this change.

Examples with the future tense:

• scuabfaidh sé - he will sweep
• pógfaidh sé - he will kiss
• scríobhfaidh sé - he will write

The consonants l, n, and r also become voiceless before an [h] sound, though this is not always reflected in spelling.