In the early 80s, when I wrote for the first time an address book app, in 6809 machine language no less :-P, I was testing the app by adding the phone numbers of friends and family from rote memory. A friend of mine, watching what I was doing, finally asked me "Da heck you need an address book for anyway? You got them numbers all memorized!"... Of course, I was a teenager, and back then it was easy (besides, it used to be one phone number per person, not a handful...). I seem to have a couple of mnemonics for phone numbers, depending where and how I use them. Numbers I [used to] dial (old telephone on a land line), I usually have a physical memory of it: the index finger knows which buttons to press in which sequence. Don't ask me the number, ask me fingers! Then there is the ubiquitous speed-dial mnemonics. Instead of memorizing the numbers, I memorize[d] the speed-dial numbers attached to them. Then there are the numbers I have to recite to others: my own numbers, the company's etc... Those I usually memorized in the language of the probable audience: local numbers back then in Korean [now mostly in French], and international ones in English. The fact that 5 sounds in Korean like 0 (oh) didn't help either... Even reading the title of your post, I had difficulties visualizing the number because of that 'oh' :-) When I was a kid, France had 6-digit numbers. Now we're up to ten. We used to split them into three 2-digit numbers: thirty-two, fifteen, fifty-six. It had kind of a rhythm to it. When France Telecom upgraded the system to 8 digits, people usually made a small pause after the first 2-digit number, and then go on with the 3 other numbers, as before: fifty-five..... thirty-two, fifteen, fifty-six. It still had a recognizable rhythm. Now that we're up to ten, with a leading 0, I've seen and heard most of the possible variations. So when somebody spell out a phone number, and the other person spells it back to make sure it's correct, you'll often hear to different rhythms, like xx... yyzz.... ttnn and then xxyy... zztt... nn I dunno know if I make much sense to non-French -- I think you had such and addition of digits in the UK, so maybe there is/was a similar phenomenon. Anyway, memorizing numbers by spelling them out loud isn't the same fun as it was ;-)