In 2017, Scripps noted in their rules for registrants that the new 'official source' for words would be the online version of Merriam-Webster's Unabridged dictionary at http://unabridged.merriam-webster.com/ instead of the previously used printed version of Webster's Third New International.
There are some substantial differences between the online version and the printed dictionary which amounts to about 33% of the words in any list. Here are some of the elements that have changed.
Discontinuation of the d-stop in pronunciations
They have entirely dropped the stopped-d pronunciation in words like butter and meter. In the printed dictionary, these showed as \ˈbəd-ər\ and \ˈmēd-ər\ for their first pronunciation, and also showed \ˈbətə-\ and \ˈmētə-\ as alternate pronunciations. In the online dictionary, they are simply shown as \ˈbə-tər\ and \ˈmē-tər\ with no alternate pronunciation. There are literally hundreds of these.
Change from the schwa dot ə̇ diacritical mark to schwa ə
Many words that formerly used the schwa dot, ə̇ (a diacritical mark that we formerly transcribed to an 'i' sound), now have changed that to the schwa, ə. For instance, the word cupid which was shown as \ˈkyü-pə̇d\ in the printed dictionary, is now shown as \ˈkyü-pəd\ in the online version and these are pronounced differently with the schwa sounding more like a "u" than an "i." Again, there are a large number of words this change has affected, such as rabbit, pundit, bandit, zenith, tariff, catkin, palette. These now have the schwa sound, not the ‘i’ sound.
Parts(s) of speech changes
Many words from geographic terms have changed their part of speech from adjective to noun, and they are listed as "geographic entries" in the online dictionary. We found a very large number of Japanese geographic terms whose pronunciation changed with the online dictionary. Kanazawa changed from \kä-ˈnä-zä-wə\ to be \kä-ˈnä-zä-wä,ˌkä-nä-ˈzä-wä\ which is a significant difference. Nishinomiya, Hiroshima, etc. made this type of change from adjective to only be acknowledged as a noun and changed something in the pronunciation, often the last syllable.
Words that were originally optionally capitalized are often shown only capitalized in the online version, but this currently does not affect NSB spellers.
Completely changed words
The word coyote in the printed dictionary was \ˈkī-ˌōt also -ˌyōt sometimes ˈkȯiˌ-, usu -ōd.+V; kīˈōd.(ˌ)ē, -ˈō(ˌ)tē also -yō- sometimes kȯiˈ- or kə̇ˈ- or kē ˈ. In the online dictionary, the pronunciation is simply \kī-ˈō-tē chiefly Western ˈkī-ˌōt\ .
Words with no pronunciation and/or no audio
The most distressing of all the changes would be the number of words in the online dictionary that have no pronunciation shown, and many, many of these have no audio either. This is pretty challenging for spellers. Many of these are compound words, and one can 'guess' that it is made up of the two separate words, but guessing does not really relay where the accented syllable falls. More difficult are the words with no pronunciation shown and no audio that are not at all familiar, such as iroha, tenno, adsuki bean, genro, Ashura, gyokuro, Shin-shu and a large number of other Japanese geographic words.
Present/not present words
Another alarming realization is that some words have been left out of the online dictionary that were previously included in the print version, and when you enter the word in the online search, it pulls up a list of possibilities, including exactly the word you entered, but when you click on it, there is no entry in their dictionary. Words of this ilk include Yokkaichi, Takaoka, Omuta, Tokushima, Otaru, Ube, Morioka, and on and on.
On the positive side, the online dictionary gives us a wealth of “new” words that were not in the printed dictionary and we think this is the primary reason Scripps has changed to this dictionary. For additional help in finding new or revised words in the online dictionary, we recommend Webster Detector. Good luck and good spelling!