As a New Zealander, the PGP list is unfriendly because there are plenty of words that are hard to spell, or are too US centric.
dogsled (contains silent d, and sleigh might be a British spelling)
Galveston (I've never heard of the place)
Geiger (easy to type i before e - unobvious)
Wichita (I would have guessed the spelling began with which or witch)
And why did the designers not make the words have some connection to the numbers e.g. there are 12 even and 12 odd words beginning with E - add 16 more E words and you could use E words for E0 to EF. Redundant encoding like that helps humans (and would help when scanning for errors or matches too)
I imagine it is even harder for ESOL people from other countries! I am sure the UI has completion to help - but I wouldn't recommend using that list for anything except a pure US audience.
It should be discussed like this! It's clear that the w3w people didn't even do the bare minimum here!
The thing is, once you agree that some words are subpar or need translations, you can do a 1-to-1 mapping.
The problem with What3Words is that supporting the original word set will always be a pain even if they release a v2 word set with a 1-to-1 mapping (I believe they've already released versions for other languages?)
re: Geiger- parsing it could trivially accept misspellings of words
Making a word list that could work well for speakers different English dialects and for speakers of English as a second language sounds really hard. Has such a list as been made?
Probably it is too hard so we will continue to ignore the problem.
I'm particularly a fan of the PGP word list (it would definitely require more than 3 words for this purpose, though) because it has built-in error detection (of transposition, insertion or deletion): Separate word lists are used for "even" and "odd" hex digits. This makes it, IMHO, fairly ideal for use over verbal channels. From the wiki: "The words were carefully chosen for their phonetic distinctiveness, using genetic algorithms to select lists of words that had optimum separations in phoneme space"
It sounds like the w3w folks did not do any such thing
EDIT: According to my napkin math, 6 PGP words should be enough to cover the 64 trillion coordinates that "what3words" covers, but with way better properties such as error detection and phonetic incongruity (and not only that, it is just over 4 times larger, which means it can achieve a resolution of 5 feet instead of 10)