Petrol and patrol are written very similarly, though completely and obviously different in meaning. My question here is actually about the accent on these words.

Why is petrol stressed on PE, and patrol stressed on TROL? What are the grammar rules applied here?

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    I think this is a bit of a "non-question", since the two words you've asked about are simply different words, so there's no reason why they should be enunciated with the same stress pattern. Now if you'd asked about the two different ways of pronouncing what we might think of as the same word, such as present, update, record, permit,... – FumbleFingers Oct 8 '18 at 18:46
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    @FumbleFingers All languages have pronunciation rules. English isn't different. Sometimes, a word changes its pronuciation because it's a verb, or an noun (record as verb or record as a noun). Other times, they'll vary according to the an extra vowel (cut x cute). Some other times, they'll vary depending on the origin of the word. Petrol and patrol are equal, except for the "e" in one, and the "a" on the other. So, my question is about which rule applies on the stress difference between them, once they both have two syllables, start with "P+vowel" and finish with "TROL". Got it?! – Loureiro Gui Oct 8 '18 at 18:55
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    @LoureiroGui Although there is some consistency, many "rules" are simply "because that's how we ended up doing it." Exceptions abound everywhere. If you're looking to apply logic to more than just some parts of English, you're going to be disappointed. – Jason Bassford Oct 8 '18 at 20:54
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    Very often the stress pronunciation varies according to whether the person speaking is British or American; or comes from London or Lancashire. For example Americans talk about "the WEEKend", whilst we say "weekEND". So if the same word can vary simply according to who is saying it, then why shouldn't two entirely different words, with different meanings have different stresses? – WS2 Oct 8 '18 at 20:55
  • Well, in he world petroloum, the trol syllable is stressed. Idk if that helps, though, but I’m just pointing it out :\ – Mr Pie Oct 9 '18 at 5:12

There is no reliable way to predict the stress pattern of a polysyllabic word ending in a single vowel letter (i.e. not a vowel digraph) followed by a single L. Some such words have final stress (e.g. lapel, canal, cabal) while others have earlier stress (e.g. label, camel, vial, metal, channel).

There also isn’t any simple link between pronunciation and etymology for words with this spelling pattern. As Janus Bahs Jacquet mentions in a comment, older loans from French are less likely to have final stress than more recent loans.

I think non-final stress is generally more regular for words with this spelling pattern, except for prefixed verbs such as impel, propel, extol, annul, compel.

Even though patrol isn't prefixed, I think the fact that it is commonly used as a verb might have contributed somewhat to its having final stress—both as a verb and as a noun. Even though there are some English noun-verb pairs that are distinguished by stress, such as record (v.) vs. record (n.), it's actually also common for nouns to have the same stress as identically-spelled verbs, as with report, surprise and account.

  • Even with a vowel digraph, it's unpredictable; consider ideal and ordeal. – Peter Shor Oct 8 '18 at 22:11
  • @PeterShor Would you stress those different? They’re both stressed on the final syllable to me. – Janus Bahs Jacquet Oct 8 '18 at 23:12
  • @sumelic There is an indirect link with etymology, though, in that final stress in French loans becomes increasingly likely the newer the loan is. All the initially stressed examples you give here, for instance, are from the 14th century or earlier, whereas the finally stressed ones are all from the 15th century or later. In Old English, initial stress was the norm, and earlier French loans were forced to fit in; eventually there were so many loans and so much diglossia that stress patterns were maintained in new loans, leading eventually to the mess that is modern English stress. – Janus Bahs Jacquet Oct 8 '18 at 23:18
  • @Janus: I stress ordeal on the first syllable. Merriam-Webster says both are possible, and it looks like I'm in the minority. – Peter Shor Oct 8 '18 at 23:31
  • @PeterShor Interesting! I don’t think I’ve ever heard that – it sounds quite foreign to me (unlike, say, adult, where both sound exactly as natural as each other). – Janus Bahs Jacquet Oct 8 '18 at 23:32

Petrol is a light fuel oil that is obtained by distilling petroleum and used in internal combustion engines. The word is thus derived from petroleum.

Petroleum is a noun-adjunct, noun pair from

Ancient Greek: πέτρα, translit. petra, "rock" and Latin oleum, "oil" from Ancient Greek: ἔλαιον, translit. elaion.

Naturally, the stress is on the noun and not the noun-adjunct.

OTOH, patrol is from

Mid 17th century (as a noun): from German Patrolle, from French patrouille, from patrouiller ‘paddle in mud’, from patte ‘paw’ + dialect ( gad)rouille ‘dirty water’.

The paddle is the main subject and the dirty water is just a qualifing assistance. Patol is stressed on the paddle, pat-.

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    Let me point out that patrol is not accented on the pat- but on the -rol, just the way it was in French and German when we borrowed it from these languages. – Peter Shor Oct 11 '18 at 13:46

I think they both follow their original pronounciation from French from which the terms derive:


gasoline," 1895, from French pétrol (1892);


1660s, "action of going the rounds" (of a military camp, etc.), from French patrouille "a night watch" (1530s), from patrouiller "go the rounds to watch or guard."


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    French words don't actually have any phonemic stress accents. Pronounced in isolation, they're always stressed on the last syllable. That é doesn't say where the accent is, like it would in Spanish; rather it tells you which of the two e vowels in French to use. So saying that the accent came from the French isn't really an adequate explanation here. – Peter Shor Oct 8 '18 at 19:18
  • @PeterShor - yes, but in the specific case of the two terms above the syllables stressed are the same as in English...a coincidence? Maybe – user067531 Oct 8 '18 at 19:21
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    In case you didn't understand my last comment, the French stress both patrouille and pétr0l on the last (the second) syllable. – Peter Shor Oct 8 '18 at 19:22
  • @PeterShor - en.m.wiktionary.org/wiki/p%C3%A9trole – user067531 Oct 8 '18 at 19:23
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    @user240918 The Wiktionary link tells you nothing. As Peter’s first comment says, French words are usually said to not have phonemic stress; phonetically (in isolation especially), they are always stresses on the last syllable. These two words in French are no exception: they are stressed on the same syllable in French. – Janus Bahs Jacquet Oct 8 '18 at 23:10

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