PUL does not use the verb coinneáilt, and prefers cimeád in the meaning of “to keep”. However, coinneáilt is used by Amhlaoibh Ó Loíngsigh, Dónall Bán Ó Céileachair and Diarmuid Ua Laoghaire (second cousin of PUL). It seems the rule in Muskerry Irish about preferring not to use the tense slender n (N’, or /ŋ’/) after a preceding guttural consonant applies hapharzardly with this verb. As far as I can find out this rule applies more often when the syllable after the slender n takes the stress, but in fact most forms of coinneáilt show this rule can be applied, from a brief perusal of Scéalaíocht Amhlaoibh and Seanachas Amhlaoibh.
These forms may be demonstrated:
1. Present: coiním or coinním, coiníonn sé or coinníonn sé (either lax or tense slender n)
2. Past: do choinibh sé or do choinnibh sé – both lax and tense slender n are found. The other personal forms, eg do choinníos or do choiníos are not attested in those works (both of these works were edited in a semi-phonetic manner and if these words had appeared the pronunciation would have been shown).
3. Future: coineóidh sé – only a lax slender n is found (/ki’nʹoː/). There are no examples of coinneóidh sé.
4. Conditional: no forms are found. Presumably these are like the future and are: do choineódh sé.
5. Past habitual: both do choiníodh sé and do choinníodh sé are found (both tense and lax slender n are possible).
6. Imperative: coinibh and coinnibh are both found: /kinʹivʹ~kiŋʹivʹ/. [Note: it is not coinnigh].
7. No subjunctive forms have been found, but these can be guessed from the present and the past habitual.
8. Verbal noun: coinneáilt is the only form attested, with a tense slender n throughout those works: /ki’ŋʹaːlʹh/.
9. Participle: coinithe and coinnithe are both attested: /kinʹihi~kiŋʹihi/.
The reluctance to use “ng” after a k or a g also applies to ‘na choinnibh, which is not related to this verb, but which is found as both ‘na choinibh and ‘na choinnibh.