Why is PhD read as /piːeɪtʃˈdiː/ (from Oxford Dictionary) and not, for example, like /fˈdiː/ , while diagraph ph is read as /f/ in Latin and Greek words? Why do we write Ph if not to represent the /f/ sound?

There are questions about writing (like this) but not pronouncing.

EDIT: Thanks for answers. To be clear. I asked this because of it is not the three letters P.h.D. Why we read it not as /ɛf diː/?

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    To be consistent, you'd either read each letter (P - h - D) or treat it as a pseudo-word (fad). By convention, Ph.D is read as individual letters.
    – Lawrence
    Commented Nov 26, 2018 at 17:41
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    Well, the reason it’s not /fdiː/ is that syllable-initial /fd/ is not phonotactically valid in English, so that’s not a possible pronunciation of anything. It’s a good question, though. There’s no obvious way to pronounce initialisms with digraph letters, so why one strategy was chosen over another is an interesting conundrum. Commented Nov 26, 2018 at 19:59
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    In English, the initial consonant cluster of /fd/ is impossible, and would never occur to a native speaker. I have heard it pronounced [fɨd], with a minimum vowel, but just as a joke. Commented Nov 26, 2018 at 19:59
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    You can call NaCl enn-ay-see-ell, or you can call it sodium chloride, or you can call it salt, but you can't call it nackel. Commented Nov 27, 2018 at 15:58
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    @Fattie This is not an ELL question by any possible stretch of the imagination. No amount of learning English will teach you why PhD is pronounced as it is, and the answer is not one that any English speaker will know by dint of being an English speaker. You may find it tedious, but it is actually a very interesting and profound question that is very much an ELU question. Commented Nov 27, 2018 at 20:27

2 Answers 2


PhD (or Ph. D.) is a bit of a frozen expression or idiom. The expression doesn't abbreviate the English phrase "Doctor of Philosophy". If it did, then it would be something like "DP" or "DoP". Instead, PhD retains the structure of the medieval Latin Philosophiae Doctor, which dates from the 17th century.

As to why the Latin abbreviation for "Philosophiae" was "Ph" rather than just "P"? "Philosophia" was a word borrowed into Latin from the Greek, and in Greek the word is spelled "φιλοσοφία", the first letter being φ. In Greek that's a single letter representing an aspirated π, and is transliterated into Latin as ph.

Since the abbreviation PhD does not match up with the English phrase it supposedly abbreviates, the pronunciation of the abbreviation has diverged from the pronunciation of the phrase.

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    @Joker_vD More like late Renaissance German scholars, but yeah. Commented Nov 26, 2018 at 20:53
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    "that's a single letter representing an aspirated π" ... or at least it was at some time in Greek history. Even after the Greek pronunciation of φ changed, the Latin transliteration ph was retained.
    – GEdgar
    Commented Nov 26, 2018 at 21:38
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    As a Greek, I can safely upvote this.
    – gsamaras
    Commented Nov 27, 2018 at 9:55
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    then it be something like "DP" or "DoP" - Note that Oxford University (and possibly others?) awards DPhil instead of PhDs Commented Nov 27, 2018 at 16:11
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    @ChristopherSchultz Most Germans habitually use the letter c for a great many things. Commented Nov 27, 2018 at 20:29

Because it is an initialism so you read out each letter ("DVD" is pronounced "dee-vee-dee", not "dvid"; "US" is pronounced "you-ess", not "uhs"). Your proposed pronunciation could be used were it an acronym.

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    Well, PhD isn't a strict English initialism since Ph isn't an English letter. This answer rather begs the question, why do we consider PhD an initialism and not an acronym? Commented Nov 26, 2018 at 17:53
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    Likely to distinguish it from other more comment "P-D" abbreviations, like "police department" or "private detective;" the "H" is likely explicitly called out as a courtesy to the listener, like the phrase "Phat as in p-h"
    – Carly
    Commented Nov 26, 2018 at 17:55
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    But even PD isn't an English initialism for Doctor of Philosophy. If it were, it would be DP or DOP. It retains the structure of the original Latin Philosophiae Doctor which predates the other "PD" abbreviations by a long while, so it can't just be "courtesy to the listener". Commented Nov 26, 2018 at 19:13
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    Now to clarify whether one says "P, aitch, D" or "P, hetch, D".
    – Beanluc
    Commented Nov 26, 2018 at 20:16
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    Who says "hetch" for H? Commented Nov 26, 2018 at 21:14

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