When SIP was designed for internet telephony, the feeling was to get rid of the phone number and replace it with IDs with the form of email addresses. E-mail addresses are of course easier to remember and read, though as a downside they tie your address to a domain, which is fine if it's yours, but silly if it's your service provider's.
However, to much surprise, handsets with numeric keypads not only continue to dominate the phone, but their use is growing. So much that complex "texting" systems have been designed and come with phones to let people enter text messages with the keypad.
In addition, popular IP phones feature not full keyboards, but traditional keypads, even though they have room. Mobile phones largely won't have keyboards for size constraints. As a result, IP phone users are using services like Free World Dialup and SipPhone so they can have phone numbers again, the thing we wanted rid of.
There is another ancient system involving phone numbers based on the letters Bell put on the keypad. Starting with Pennsylviana-6-5000, and moving to numbers like 1-800-FLOWERS.
Of course there are other answers to dialing -- menus, speech interfaces and so on. But if dialpads are with us for a while longer, does it make sense to rethink the system of finding words to spell out phone numbers?
If we use the existing system (with perhaps some minor mods) we could get a wide selection of spellable words by having longer numbers. No reason you can't have multiple numbers -- a "normal" 7 (or 10) digit number and then a longer number that is easier to remember but harder to key because it's longer. Thus I could probably have "BRADTEMPLETON" 2723-836753866 as a phone number, as well as my regular 7 digit number for use in systems that can't handle long numbers. Cell phones of course can easily have the length of numbers extended, but even ordinary phones can do this easily with a * or # code.
Of course the spell a word system has name collisions, so not everybody can get their preferred choice of name, but everybody can have an easy to remember string, I would venture. (Like with domain names.)
Actually, many would not want to use their "guessable" name if they want an unlisted number. So they might pick "Way to get Brad" or anything else available.
We might also tweak the system to make more numbers usable. We could do a complete redesign so that each digit has one "popular letter" from the set "ETOAINSHRD" and two letters from the less popular sets, but this would take quite a while for people to re-learn.
We could also do minor tweaks. For example, assign "O" to zero, and "I" to one, and stick "Q" on the end of six, slightly out of order.
These long names would be for rare use. Generally for dialing a person the first time, after which they can go in your address book, either for speed dialing or "completion" -- where you start to dial a number and it offers to finish it off when you have enough digitsl to differentiate it from the rest of your book.
So if I used that long number above, and you asked for my number, I could just tell you "Brad Templeton" and you could enter all those digits the first time you called me, but later, after you had entered 27238, for example, the phone would offer to complete it with the rest.
Or if you had old phone equipment, you could use my old-time 10 digit number as before.