It is obvious that both 'recycle' and 'bicycle' have a common element 'cycle'. 'Cycle' on its own is pronounced with a long 'I' sound /aɪ/. 'Cycle' in 'recycle' is pronounced how 'cycle' is normally pronounced. That is, with a long I /aɪ/. But the 'cycle' in 'bicycle' is pronounced with a short 'I' sound /ɪ/ (like kit, hit, sit). In phonetic notation:

  • Recycle → /riːˈsʌɪk(ə)l/
  • Bicycle → /ˈbʌɪsɪk(ə)l/

Why does this happen? Can someone give some information?

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    Please do let me know if I need to fix anything in my post or if it is off topic or any other problem. I will check for answers tomorrow. Thanks!
    – user126531
    Feb 14, 2021 at 13:15
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    Nothing is wrong with your question. It is a surprise for me that "bicycle" is pronounced that way. I have been saying it as BAI-SAI-KUHL my whole life.
    – user119042
    Feb 14, 2021 at 13:19
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    @Sphinx you never heard anyone say in any movie or sing in any song /ˈbʌɪsɪk(ə)l/? I find that extraordinary.
    – Mari-Lou A
    Feb 14, 2021 at 21:17
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    simply google the famous Queen pop song for the usual pronounciation
    – Fattie
    Feb 15, 2021 at 0:09
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    @Mari-LouA Unfortunately, the movies I watched and the songs I heard did not have "bicycle" in them. I only ever googled this word yesterday when this question was asked. I have been saying it BAI-SAI-KUHL because of English spelling. That is, it is misleading most of the time. From void's answer, I also learned that "infinite" is pronounced as IN-FIN-IT not IN-FAI-NAIT (I have been saying this wrong too!!). Learned so much from this question!
    – user119042
    Feb 15, 2021 at 5:09

3 Answers 3


This has to do with English stress patterns and prosody. English stress patterns are enormously complex and have many, many, many exceptions.


'Bicycle' has a short vowel in its second syllable because the prefix bi- is a stress-bearing prefix and can take primary stress (prominence). So when the primary stress moves from the cy to bi-, the cy gets unstressed and the diphthong [] gets shortened to [ɪ].

The diphthong in the second syllable of 'recycle' doesn't get reduced because the prefix re- doesn't often take primary stress, so the primary stress remains on the first syllable of -cycle.

Full answer

There are two main kinds of syllables on the basis of loudness; stressed and unstressed. A stressed syllable is the prominent/loudest syllable in a word. Not all syllables in English words receive the same level of loudness (i.e. all syllables in a single word cannot have primary stress).

There are three levels of stress in English:

  • primary stressed syllable: the loudest syllable in a word
  • unstressed syllables: syllables that don't have stress at all
  • secondary stress: syllables that aren't unstressed, but aren't as loud as primary-stressed syllables either (lie in between the two)

In the IPA, primary stress is represented by a preceding superscript vertical line [ˈ] while secondary stress by a preceding subscript vertical line [ˌ]. So the word pronunciation can be transcribed as [prəˌnʌnsiˈjeɪʃn]: the second syllable has secondary stress and the second last syllabl has primary stress.

The word 'cycle' is stressed on the first syllable and is pronounced /ˈsaɪkəl/ (with the diphthong [aɪ]).

The diphthong [] (as in bite) rarely occurs in an unstressed syllable. It has a systematic relationship with the short vowel [ɪ] (as in kit). This relationship is reflected in many words such as f[]nite - inf[ɪ]nite and many other remnants of Trisyllabic Laxing; div[]ne-div[ɪ]nity, der[]ve-der[ɪ]vative, and in dr[]ve-dr[ɪ]ven etc.

From this relationship, we can infer a general rule of thumb that [aɪ] will only occur in a stressed syllable and when that syllable gets unstressed, [aɪ] will get reduced to [ɪ].

The reason why 'bicycle' is pronounced /ˈbaɪsɪkəl/ is that the prefix bi- is a stress-bearing prefix and can take primary stress. Also note that English has a strong tendency towards antepenultimate stress. It means that English words tend to be stressed on the antepenult (third-last syllable).

'Cycle' has primary stress on its first syllable and when the prefix bi- is prepended to it, the primary stress moves from cy to bi-, leaving the cy unstressed. And as I said above, when a syllable having [] gets unstressed, the diphthong [aɪ] usually reduces to the short vowel [ɪ]. That's what happens in bicycle.

Re- on the other hand does not often take primary stress1, so when it's prepended to cycle, the primary stress remains on the cy. That's why the re- remains unstressed and the cy becomes the prominent syllable.

However, the cycle in unicycle, quadricycle, motorcycle is pronounced with the diphthong []. It has been explained in this answer on ELU [Modified]:

motorcycle, quadricycle and unicycle consist of a pair of trochees: MO-tor-CY-cle, QUAD-ri-CY-cle, U-ni-CY-cle. The primary stress in these words falls on the first syllable, but the secondary stress falls on the first syllable of -cycle. In this context the vowel retains its full pronunciation i.e. it still receives stress, so the diphthong doesn't get reduced.


  1. Re- can take primary stress in some words, as Colin Fine and Canadian Yankee pointed out in the comments below. It seems to me that disyllabic nouns that have the prefix re- have primary stress on the re-, whereas disyllabic verbs don't have primary stress on the re- (cf. REcord and reCORD). I think trisyllabic nouns having the prefix re- follow the antepenult stress rule, so they get primary stress on the re-.
  • Perhaps I am ignorant but I am not clear how that covers unicycle and quadricycle as opposed to bicycle and tricycle. I know that was not what the OP asked.
    – mdewey
    Feb 14, 2021 at 13:54
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    Also see finite - infinite, potent - impotent
    – Void
    Feb 14, 2021 at 14:10
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    Re- can take primary stress, in research (some pronunciations) and reject, but these are old words, not obviously containing the prefix re-, "again".
    – Colin Fine
    Feb 14, 2021 at 14:20
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    @ColinFine - In addition to your examples, I can think of other, newer words that have a stressed re- as initial-stress-derived nouns: rerun, retread, redirect, refill, recount. I think it's just wrong to say that "re- can't handle initial stress," although I think you can say that it usually doesn't take stress in a verb, but it can in a noun. Feb 14, 2021 at 15:02
  • @CanadianYankee: That's a good point! I'll add that to my answer.
    – Void
    Feb 14, 2021 at 15:09

There's often not much point in asking why a word has a particular pronunciation. There's rarely any logic or pattern.

Recycle is a word recently created (1920s, but only being used in its modern meaning in the 1960s). It means "cycle again" and the suffix "-cycle" has the same meaning as the word (meaning to go around).

Bicycle is created on a pattern created by the earlier "tricycle" in the sense of a three-wheeled carriage. Its pronunciation was influenced by French, or rather tricycle was a word created in French and borrowed into English, and then anglicised. Bicycle has a different stress pattern, and the suffix "-cycle" means "wheel", so a bicycle was originally an adjective "a bicycle velocipede" not a noun (the verb "to cycle" meaning to ride a bicycle is a back-formation from bicycle). So "cycle" is not really a common element. "Bicycle" is also 100 years older than recycle, so has had 100 more years for the pronunciation to be modified. The difference in stress results in different vowels.

So the reasons are partly random, partly historical. Essentially, they are different words which are pronounced differently, despite the similarity in spelling.

  • I would agree—looking at when words entered English is the right approach here. Re-cycle, and also up-cycle, have clear roots and prefixes. There are plenty of bi- words (bisexual, bifocals, bipolar, biyearly) that allow for more varied stress patterns.
    – Ted Pal
    Feb 19, 2021 at 22:16

Short Answer: In English, we often stress the first syllable of nouns; the second syllable for verbs. "I went to the store and bought a RECord." "I went to the studio to reCORD my new album."

BIcycle is a noun; reCYCLE is a verb.

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    This! It's a much simpler explanation of what's going on here than the other answers. And even if bicycle is used as a verb (to ride one), it's a verb formed from a noun in the sense of "to do the thing you do with that noun", and these follow the pronunciation of the noun. Feb 15, 2021 at 15:38
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    Simple, but probably too simple - English pronunciation (and spelling, grammar) usually owes more to history than to logic.
    – MikeB
    Feb 16, 2021 at 16:56
  • "I biCYCled to the record store," or more commonly, "I cyCELD to the record store?" Feb 17, 2021 at 14:56

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