What is the standard rule, if there is one, for pronouncing words beginning with the prefixes com-, col-, cor-, con-?

Very often these words have an /ɒ/ vowel, like in the word hot - in Gen American, I think it's the vowel /ɑː/. Other times they may have a schwa, /ə/, like the first vowel in amazing. Sometimes they seem to have a syllabic consonant, /m, l, r, n/.

Sometimes there even seem to be two words which are spelled the same but have a different pronunciation. For example content meaning "happy" and content as in "the content of the lecture", for which Cambridge Dictionaries gives the transcriptions /kənˈtent/ and /ˈkɒntent/ [US:/ˈkɑːntent/] respectively.

Here are some examples with transcriptions from Cambridge Dictionaries Online:

  • common /ˈkɒm.ən/
  • commercial /kəˈmɜː.ʃəl/
  • colleague /ˈkɒl.iːɡ/
  • collection /kəˈlek.ʃən/
  • correlate /ˈkɒr.ə.leɪt/
  • correct /kəˈrekt/

So my question is:

  1. Is there any rule for whether a schwa or full /ɒ/ or /ɑː/ is used?
  2. Are there generalisations that can be made which will help me have a good guess at which to use.
  3. Are there any rules that will enable me to tell in certain restricted situations.
  4. If I'm unsure about a particular example, would I be better to go with a schwa or a full vowel. Why?
  • 2
    Written words are not pronounced. Spoken words are written down. And the spelling encodes many different things, of which a poor approximation of the pronunciation is just one. Consequently, there is absolutely no reliable way to figure out the pronunciation of a word by looking at its spelling. In every language, not just English. In short, this question is unanswerable at best, and nonsensical at worst. – RegDwigнt Aug 25 '15 at 8:47
  • 1
    Which words? You haven't given any. Which ones have you encountered that seem problematic, or contradictory? – Brian Hitchcock Aug 25 '15 at 9:24
  • 3
    @RegDwigнt That's seems a bit deliberately unhelpful! There are indeed generalisations we can make to help us decide whether or not the first syllable is going to contain a schwa or not when seeing a word for the first time. – Araucaria - Not here any more. Aug 25 '15 at 13:31
  • 3
    @RegDwigнt Many languages have a good enough spelling pronunciation correspondence for us to be able to accurately predict what phonemes are going to be present in the word. – Araucaria - Not here any more. Aug 25 '15 at 14:10
  • 2
    @Araucaria I sure do, if only because of your implied promise of a great answer. Looking forward to it :-) – oerkelens Aug 25 '15 at 14:47

It looks like, from your small sample here that at least in General American, no stress on the initial syllable gets pronounced with the schwa /kə/, and with stress it is /ˈkɒ/.

And that is what the rule is,The rule is usually that a vowel in unstressed positions often gets converted to schwa (and such a rule pretty much answers all your questions, 1 through 4).

What the rule is for when there is stress on the 'with' prefix, it depends on the whole word: two syllables stress in on the first, three syllables stress on the second.

  • That stress rule doesn't work. For two-syllable words, generally the stress the second syllable for verbs (compare the noun "content" and the verb "contain"). Two-syllable adjectives may take iambic stress ("content,""correct," "complete"). Also, three syllables doesn't mean stress on the second syllable: there are many three-syllable words like "competent," "correlate," etc. where the stress is on the first syllable. – herisson Sep 8 '15 at 21:37

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