Comparative review of English pronunciation dictionaries

What is a pronunciation dictionary and why is it useful?

A pronunciation dictionary is a specialized type of dictionary that does not contain definitions or example sentences. It only contains phonetic transcriptions and recordings which tell you how to pronounce words correctly.

A pronunciation dictionary has the following advantages over a general dictionary:

• More words. A pronunciation dictionary can list pronunciations for more words than a general dictionary. It can include first names, last names, geographical names, company names, trademarks, etc.
• Word forms. It can give the pronunciations for inflected forms of words — e.g. starts, started, starting — not only for the main form like start. This is especially helpful for beginner learners, who can learn that e.g. goes ends in /z/, not /s/.
• More pronunciation variants. A pronunciation dictionary can list more ways to pronounce the same word. Specifically, it can explain how to pronounce a word in a sentence. For instance, and is pronounced /ænd/, but “and all” may be pronounced /ənˈɔ:l/.
• More precise transcriptions. It can use additional symbols to give more detailed information on pronunciation.
• More authority. One can expect that a pronunciation dictionary will contain fewer errors in transcriptions than a general dictionary.

Do you need a pronunciation dictionary?

In truth, it is hard to say that a pronouncing dictionary is indispensable for every English learner. You can find the pronunciations of most words in a good learner’s dictionary. For proper names, you can try Google searches, Internet forums and sites like Inogolo or Forvo.

You will make the best use of a pronunciation dictionary if you consult it when you have reasons to doubt your regular dictionary (or dictionaries). For example, when your dictionary gives a different pronunciation from the one you hear from native speakers, or when there are differences between two dictionaries, you can count on a pronunciation dictionary to give you an authoritative answer. If a pronunciation dictionary lists a pronunciation first, it is probably the most common one. If it does not list a pronunciation, it is probably quite rare.

The dictionaries

• Cambridge English Pronouncing Dictionary by Daniel Jones (17th edition, 2006)
• Longman Pronunciation Dictionary by J.C. Wells (3rd edition, 2008)

The Cambridge English Pronouncing Dictionary (EPD) is a classic work on English pronunciation. Its first edition, written by Daniel Jones and published in 1917, used symbols of the International Phonetic Alphabet to represent the pronunciations of English words. This system of transcription was further improved by A.C. Gimson in the 13th edition (published 1967). Gimson’s system is now used, with certain modifications, in nearly all English dictionaries published in the UK.

Next to the EPD, the Longman Pronunciation Dictionary is a newcomer — its first edition was published as late as 1990. The author of the LPD, John Wells, is probably the most famous British phonetician living today.

In this review, I have focused on the software (CD-ROM) versions of both dictionaries, because paper dictionaries are slow to use and have no audio recordings.

Review criteria

I looked at the following features in all the dictionaries:

• Accuracy and completeness of phonetic transcriptions. The dictionary should list all common pronunciations of a word in both British English (RP/BBC English) and American English (General American). The first pronunciation listed should be the one most frequently heard among educated native speakers. Major differences between sounds should be shown, even if they are non-phonemic.
• Quality and coverage of recordings. Audio recordings should sound clear (no technical defects). If only one recording is given, it should reflect the most common pronunciation variant. Ideally, there should be a recording for each British and American transcription and for each word form (-s, -ed, etc.).
• Coverage of proper names and rare words. Since a pronunciation dictionary is often used to look up first names, last names, place names, acronyms, trademarks, and other rare words, it should contain as many such entries as possible.
• User friendliness. The software should enable the user to perform all the common tasks (looking up a word, playing a recording, etc.) easily and without unnecessary clicking. It should offer all the expected features (like copy & paste) and should support all the expected input operations (standard keys, drag-and-drop, scrolling with the mouse wheel).
• Responsiveness. The software should do its job without annoying delays.
• Sound search. The user should be able to search for words using phonetic symbols. The search should enable the user to search for things like words ending in /-oʊp/ or words which contain the /ʌ/ sound in an unstressed position.
• Layout. Entries should be laid out in a clean and readable way. The user should not feel overwhelmed by interface elements.
• Price.

Testing methodology

Phonetic transcriptions

I checked the dictionaries against a list of 88 specific questions, for example:

• Does the dictionary give all the common pronunciations of employee?
• Does the dictionary show the difference between the British and American pronunciation of shone?
• Does the dictionary list all the weak (unstressed) forms of the word him?
• Does the main American transcription of office start with a different vowel than the one in lot?
• Is there a flap t symbol in the main American transcription of whatever?
• Does the British transcription of fire include the variant which sounds like /fɑ:/ or /fɑ:ə/?

Recordings

I looked up 12 “tricky” words (words with a difficult pronunciation or with many possible pronunciations) and played the British and American recordings. I checked the following things:

• Does the speaker pronounce the word clearly?
• Is the technical quality good (no noise, no compression artifacts)?
• Does the recording match the first (main) transcription for both British and American English? (I checked this on a longer list of about 50 words)
• Are there additional recordings for word forms (-s, -ed) and for compounds?

The most important factors in the grade were clarity and technical quality.

Proper names and rare words

I looked up 78 last names, first names, product names, place names, rare words and acronyms, e.g.: Oswald, Schwarzenegger, Fiennes, Nikon, Gollum, Canberra, ANSI, synecdoche, Skype, Adidas. I also verified the correctness of the transcriptions using reliable online sources.

Grading system

• A — excellent
• B — good
• C — average
• D — poor
• F — failure

Note: Grades are not comparable to those in my review of learner’s dictionaries. I used different grading scales in this review.

The comparison

Summary

The verdict is surprisingly clear-cut. The Longman Pronunciation Dictionary beats or matches the Cambridge English Pronouncing Dictionary in every category. While in most categories the difference in favor of the LPD is pretty small, the two areas in which it has a clear advantage are the quality of audio recordings and the reliability of American transcriptions.