Ok, we got a lot of words with suffix "-tion" in English like reflection or congestion.

But the way to pronounce "-tion" is different sometimes.

congestion /kənˈdʒes.tʃən/

reflection /rɪˈflek.ʃən/

SO, What are the rules to pronounce the suffix "-tion" in English, when to say "/-tʃən/" and when to say "/ʃən/"?


The most important thing to remember is to always use /ʃən/ after a vowel: for example, in words like condition or preparation – using /tʃ/ here would sound very unnatural. One word that is a weird exception is equation, where most speakers have a voiced consonant /ʒən/ for some unclear reason.

The pronunciation /tʃən/ is only required after an /s/ (in words spelled with -stion); /ʃən/ is generally used after any other consonant.

The only complication I can think of that applies to more than one word is the pronunciation after /n/, in the sequence -ntion. For many speakers, the contrast between /ntʃ/ and /nʃ/ is neutralized in some contexts, in particular after a stressed syllable (this is analogous to the "prince-prints merger"). So some speakers might pronounce a word like attention with [tʃən]; but these speakers might also have [tʃən] as a possibility in the word tension.

The difference between the pronunciation of the suffix in words like relation (or abstraction) on the one hand, and words like congestion on the other, is actually rather old (it predates the introduction of these words to English) and while it isn't reflected in the French and English spellings (which are based on the Latin etymology), it is reflected in the spelling of equivalent words in languages with more phonemically transparent writing systems:

Spanish: relación, abstracción, congestión
Italian: relazione, astrazione, congestione

Of course, the "rule" I outlined does not apply to all words that just end in the letters "tion" in English: the most notable counterexample is the word cation. However, I can't think of any counterexamples to my rule when dealing with the actual suffix -tion.

Note: I used the example words relation and abstraction rather than reflection because the latter word has alternated with reflexion in the past, giving it a more complicated history.

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  • +1 It's interesting to note that it would be very difficult to pronounce a /s ʃ/ sequence as we would normally assimilate the /s/ to the following /ʃ/. In fact any run of sibilants is unlikely. – Araucaria - Not here any more. Oct 15 '15 at 15:30

Interesting question. The examples you give, and a few others, seem to have /t/ lost between a voiceless stop (/p/ /t/ /k/) and following /ʃən/.

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    Well, the [t] was lost a long time ago in most positions, I think. After a vowel in words like "condition" or "preparation"... In French, these words have /s/, descended from earlier [ts]. The words were spelled with "cion" in some Middle English texts, which indicates that they were borrowed with [ts] (according to Wikipedia, [ts] later reduced to [s] in parallel changes in French and English). In contrast, words like "congestion" have [t] in French up to today. – herisson Oct 11 '15 at 3:55
  • @sumelic, But what happens to /t/ at the end of the stem in opt/option, act/action, etc.? Isn't that the point? – Greg Lee Oct 11 '15 at 4:08
  • oh, are you talking about synchronic analysis? – herisson Oct 11 '15 at 4:09
  • @sumelic, did you read the question? – Greg Lee Oct 11 '15 at 4:10
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    @Araucaria, yes, when you add a suffix to a stem, you expect that you'll wind up with the stem pronounced then the suffix pronounced. That is just how suffixation works in human languages. I can't fathom sumelic's difficulty with this. And as you say, it is perfectly ordinary for stem final /t/ to be lost between consonants in English -- it even happens optionally across word boundaries. – Greg Lee Oct 15 '15 at 16:10

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