English is troubled by what appears to be an unsystematic plethora of spelling rules, not to mention the rules for pronunciation. In general, there seems to be a consensus on how Greek and Latin is romanised in English, but now and then something pops up to remind us that it is not so simple. Greek κ, for instance, is often romanised as c, apparently being based on the Latin spellings. The letter υ, however, is more problematic: Mostly it is (problematically) romanised as u,¹ but in some combinations, the y is preferred, e.g.:

  • words with the prefix syn-, such as syncopate
  • words with μυ-, ψυ-, φυ-, such as myth (but music), psyche, physics
  • words with initial hard breath followed by upsilon, such as ὑποθήκηhypothek

But there are so many situations in which the expected romanisation of Greek → English υy is instead turned to υu, such as in αὐ to au, ευ/εῦ to eu, not to mention the standard romanisation of Greek words where English u is (to the best of my knowledge) always used, such as:

hypothec […] Origin Early 16th century from French hypothèque, via late Latin from Greek hupothēkē ‘deposit’ (from hupo ‘under’ + tithenai ‘to place’).

― Oxford Dictionary: ‘hypothec’

Thus my question: When should Greek υ be romanised as English u and y? I suspect the rule is that words that have been taken into the English language prefers y for monophthongs and u for diphthongs, whilst any romanisation of unassumed Greek words prefers u, but I am not sure this observation is correct, based on words such as music. My working hypothesis is that the following applies:

  1. If a monophthong and borrowed either directly from Greek or via French, the preferred spelling during the great spelling reform was y.
  2. If a diphthong, the preferred spelling was u.
  3. If borrowed directly from Latin, the word having been naturalised in Latin, the preferred spelling was u.


¹ By this, I also refer to the transliteration rules that usually are followed, as per the quote, in which υ → u is the standard method.

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    I’m not sure I agree with your statement that upsilon is mostly romanised as u in English – I would have said that y is the more common. The name upsilon itself is one case where it is indeed romanised as u, but I can’t think of many others off the top of my head. Note that in Classical Greek, upsilon was pronounced [y] except in diphthongs, where it was [u ~ ʊ ~ w], so it makes sense that it’s always romanised u in diphthongs. (Note: in music and muse, the u represents Gk. ου [u], which is usually thus transcribed.) Commented Jul 2, 2019 at 14:26
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    @JanusBahsJacquet: By the way, I've heard it said that ου was probably pronounced more like it would make sense as a Greek diphthong, i.e. something more like /ow/ or /oʸ/ or similar. I don't remember in which period, though, nor with what degree of certainty. Commented Jul 2, 2019 at 15:08
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    @Cerberus Definitely never /oʸ/ – the general explanation is that υ originally represented [u] and ου represented [ou] or [oː] (as opposed to [ɔː], which is ω). Then [u] was gradually fronted to [y] (as in French) and [ou / oː] monophthongised and was raised to be more distinct from [ɔː]. But ου existed as a diphthong representing either [ou] or [oː] before υ on its own came to represent [y]. Commented Jul 2, 2019 at 15:12
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    @JanusBahsJacquet: Ah, OK. So /ou/ sounds vaguely like the /ow/ I suggested, right? // In school, we used to pronounce ου like /u/ (possibly based on the standard French pronunciation of ou?); then I learned at some point that it was really more like /o:/ (closed long o), contrasting with open ω just as closed ει contrasted with open η; but later I read somewhere that ου probably sounded originally like a 'logical' diphthong from ο and υ, which made sense to me. If, indeed, the spelling ου was invented when υ was still /u/, as you suggest, then something like /oᵘ/ might make sense. Commented Jul 3, 2019 at 1:09
  • Related.
    – tchrist
    Commented Jul 3, 2019 at 2:30

1 Answer 1


English has two sets of (conflicting) rules to translitterate Greek into Latin letters:

  1. The traditional way, which is that of classical Latin; it is mostly based on how the pronunciation of Greek was best rendered in Latin letters and how those were pronounced in Latin.
  2. A modern, less common way, in which whatever Latin letter is chosen that developed out of the Greek letter in question (and which resembles it in minuscle (lower-case) shape).

Greek ypsilon (capital Y, minuscle υ) was pronounced like French u in classical Greek (/y/ in the International Phonetic Alphabet). Latin did not have this vowel (neither does English, incidentally); it therefore used the Greek letter Y for that sound (Latin and Greek normally only had capitals). Our lower-case y is an adaptation of this capital letter.

  • Examples: hybrid, psychology, ypsilon, cycle.

However, Latin did have vowels that strongly resembled Greek diphthongs αυ and ευ, to wit, au and eu. And so Greek AY and EY were rendered as AV and EV (Latin used V for both v and u).

(A diphthong is a vowel written in two letters, even through it is really one (complex) sound. It does not sound the way the two letters would sound separately in succession; and so, while Latin A sounded like Greek A, and Latinised Y sounded like Greek Y, the Latin sequence AY would not automatically sound like the Greek diphthong AY, whereas Latin AV would.)

  • Examples: automaton, pause, eulogy, heuristic, therapeutic.

The Greek diphthong ου was apparently perceived to sound like Latin u (which sounds like German u, International Phonetic Alphabet /u/), and so OY was rendered as V.

  • Examples: Thucydides, utopia.

Note that you will probably find some exceptions in classical Latin; nobody is ever consistent 100 % of the time.

In the modern way, any Greek letter is just translitterated into whatever Latin letter developed out of it, or into that which sounds most like it in the target language. (The Latin alphabet is an adaptation of the Greek alphabet to Etruscan and other languages of Italy.) In classical Latin, c was the normal letter to render the k sound, so it was used to translitterate Greek kappa; Latin k did exist, but it was very rare. In the modern way, Latin k is used to render Greek kappa, because Latin k was originally an adaptation of Greek kappa when the Latin alphabet was developed, and because c does not always sound like k in various modern languages. The shapes of kappa and k are also almost identical. The same applies more or less to Greek υ and Latin u (although the shapes of the Greek capital Y and the modern Latin capital U are somewhat different). So any υ is rendered as u in that system.

For whatever reason this system was first used (just to easily render Greek in Latin script in case the audience couldn't read Greek, or by some authenticist movement?), it was not originally intended for creating actual words in modern languages, but only ad hoc, when indicating vaguely what an actual Greek word in Greek signified or sounded like. Nevertheless, sometimes people do create and use words so transcribed, in English and other European languages, e.g. French and Dutch. The result is the 'mess' you have observed... I believe style books always recommend the traditional system of translitteration, mainly for consistency.

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    "I believe the system was created just to easily render Greek in Latin script in case the audience couldn't read Greek"--my impression is it's not just that. I think that this kind of system became popular when English speakers became more generally aware of theories about how ancient Greek was pronounced, including the hypothesis that υ was pronounced in Koine as [y] and that this had developed from even earlier [u].
    – herisson
    Commented Jul 2, 2019 at 14:38
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    I can't remember exactly what documents I've read that led me to believe that, though. But e.g. this 2004 book uses the spelling "kuklops" and indicates that this is supposed to indicate for an English speaker the pronunciation "kook-lohps", which it says is part of a "trend that began in the twentieth century to revive the original spelling and pronunciation of Homer's proper names" (books.google.com/…).
    – herisson
    Commented Jul 2, 2019 at 14:46
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    @sumelic: Hmm I'm not sure I understand. In Coene (hah!), I believe it was pronounced more like /u/, from classical /y/—not the other way around? So you are saying this modern way was influenced by Coene? Commented Jul 2, 2019 at 14:50
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    @sumelic: Your second comment would seem to contradict that, but kook-lohps does not sound Homeric, for Homeric Y did not sound like /u/, did it? Commented Jul 2, 2019 at 14:52
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    Actually, I was mixing up Koine and classical Attic Greek. I actually meant classical Attic. The overall sequence is [u] (very early on; e.g. in PIE and Proto-Greek) to [y] (in classical Attic Greek) to [i] (apparently, this last, unrounding change happened sometime during the history of Koine Greek). English speakers who use English /u/ for Homeric υ are either just using it as a replacement for Attic [y] (similar to how French /y/ is often anglicized as English /u/), or possibly trying to represent a more archaic stage of the language than our reconstruction of classical Attic Greek.
    – herisson
    Commented Jul 2, 2019 at 14:53

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