English.SE, Hi, first time being here. I have had this confusion about the pronunciation of "a priori" and "a posteriori" for a long time, normally I just read the last vowel as /i/, however today my office mate asked me about this for he saw the pronunciation on Merriam-Webster online dictionary shows that the last vowel reads as /ai/, this reminded me that the philosophy professors whose lectures I took before didn't agree on this pronunciation either. Since I learned that Immanuel Kant borrowed these words from Latin, I wonder what is the correct way to pronounce these words in Latin or at least in a Latin'ish way.

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    We can only tell you how to pronounce them in English. Is that enough? Apr 19, 2012 at 17:08
  • @MattЭллен Yes please!
    – Shuhao Cao
    Apr 19, 2012 at 17:09
  • While I Wait for @Matt; I know plenty of people who say the words rhyming with 'me', though I'd always rhymed them with 'I' (as in 'I am').
    – Kris
    Apr 19, 2012 at 17:46
  • Listen here: howjsay.com/index.php?word=a%20priori the American way of speaking...
    – GEdgar
    Apr 19, 2012 at 19:01

3 Answers 3


The OED gives ay - pr - eye - 'or - eye as the only pronunciation. I (an American English speaker) usually say ah - pr - ee - 'or - ee (which appears in the MW pronunciation you cited), but I hear both. As for Immanuel Kant, he would have likely pronounced it differently than an ancient Roman anyhow. One of the key differences between classical and ecclesiastical Latin (the latter of which Kant certainly would have learned) is pronunciation. So, it's hard to say which one would be more "Latin" (neither is spot on).

  • You can put a " ' " in front of stressed syllables. Apr 19, 2012 at 18:06
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    As far as I know the final vowels are pronounced /i:/ ("ee") in all varieties of Latin: classical, ecclesiastical, and as borrowed into every language of Europe except English. The "authentic" pronunciation of classical Latin (as opposed to the modern Italianate pronunciation) was established by the humanists just as the great vowel shift was getting under way in English, so when the English long /i:/ made the trek round the mouth to /əɪ/ and eventually to /aɪ/ (as in "mice"), it took the Latin vowel with it for company.
    – Colin Fine
    Apr 19, 2012 at 19:49
  • @ColinFine very good point. Although (as I understand it, since I never really learned church Latin), even if the sound were the same, the long vowels would also actually be extended in length (i.e. take about twice as long to say) in classical Latin, while the ecclesiastical pronunciation would give it the same (value?) as other vowels. Do you know if this is true?
    – Cameron
    Apr 19, 2012 at 20:08
  • No I don't know, but you may be right: I suspect length did mostly disappear.
    – Colin Fine
    Apr 19, 2012 at 22:24

As a speaker of British English, I pronounce the final syllable of each the same way I pronounce the first person singular personal pronoun.


These two are among the select (?) group of foreign phrases that have been Anglicised for so long that their pronunciation has lost any connection with Latin; unless in a specifically Roman context, the A sounds like the article, and the I like the pronoun. If you really wanted the Latin, both would be short; but I wouldn't recommend it.

  • 'A’ requires the ablative case in Latin. ‘Prior’ and ‘posterior’ are third declension adjectives, so wouldn’t they be ‘priorī’ and ‘posteriorī’ in the ablative singular, that is, with long vowels at the end? Apr 19, 2012 at 18:18
  • @Barrie: there's a flaw there somewhere, since when I learnt the third declension the ablative was rege. But without getting too off-topic, I would say it would have to be an ee sound;the Romans didn't use the long i mentioned here, hence it was Gaius not *Gius. Apr 19, 2012 at 19:19
  • Adjectives decline differently from nouns, depending on the stem. For example, the ablative singular of 3rd declension 'pauper' (poor) is 'paupere', but the ablative singular of 3rd declension 'omnis' (all) is 'omnī’. Whether a vowel was long or short can be determined from Latin verse. Other than that, actual pronunciation must remain uncertain. It no doubt changed from place to place and from time to time, as does the pronunciation of most other languages. Apr 19, 2012 at 19:31
  • @BarrieEngland I think the spelling might require a macron on the o as well - ā priōrī. And Tim, I think some 3rd declension singular comparative adjectives have two forms of the ablative (e.g. fortiōre or fortiōrī both appear in the literature), see here
    – Cameron
    Apr 19, 2012 at 19:38
  • @Cameron: Correct about ā. The normal ablative ending for comparative adjectives is '-e'. 'Prior' and 'posterior' are adjectives in their own right (at least, they have separate entries in my Latin dictionary) and that probably explains the '-ī' ablative ending. Apr 19, 2012 at 19:48

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