I’m really pleased Tim, “The Man With No URI”, has started blogging, and already has pushed out some great posts. I will try and answer some of the points raised by the topical Onwards Delegation Problem, but was diverted by Tim’s aside:
B-oo-kk-ee-p-e-r incidentally, is the only word in the English language I’m aware of with three double letters in a row. I’d love to be shown others…
Unix boxes ship with a words file, which on my Mac has 234,936 entries, and a quick grep:
egrep '(.)\1(.)\2(.)\3' /usr/share/dict/words
revealed:
bookkeeper bookkeeping subbookkeeper
Scraping Wiktionary:
for i in a b c d e f g h i j k l m n o p q r s t u v w x y z
do
curl http://en.wiktionary.org/wiki/Index:English/$i
done |
grep '<li><a href="/wiki/' |
sed 's/^.*title=\(.\)\(.*\)\1.*$/\2/' > words
gave 72,018 words, with no plurals, but still only revealed “bookkeeper”.
There are a bunch of open word lists around the Web, many harvested from Gutenberg, but Moby Words, having 619,361 words and claiming to be “the largest word list in the world“, could only come up with:
assistant bookkeeper bookkeep bookkeeper bookkeeper's bookkeepers bookkeeping bookkeepings bookkeeps double-entry bookkeeping single-entry bookkeeping subbookkeeper
Oh well, I did at least try.

Nice regex.
And it seems that subbookkeeper is the only word to have four double-letters in a row.
Kitten, playing with the fluff that fell off the ball of string.
That is so weird. I was at work, and I saw the word “balloon”, and I thought - neat, that has 2 pairs of double letters in a row, I wonder if there are more, one egrep later and I saw there were heaps, so then I tried for 3 pairs and discovered bookkeeper.
Then, it is my lunch break and I visit planet intertwingly for the first time in months and see this post (a few hours after making the discovery for myself). Freaky.
This very much reminds me of RM’s (xkcd) latest blag post on Ghost.
Maybe you’ll find some alternative approaches there (the comments are extensive).
You’ve been hassling me to blog for ages, and I have finally got around to it. Hopefully I don’t distract you in this kitten-esque fashion too often. We’ll start fighting over balls of wool. This three double letter piece of trivia is one I’ve been hanging onto for about 20 years! It’s good to finally have shared.
Christopher, well done for finding a four letter one, even if it’s just a derivative…
Paul === 40-foot Kitten
Nice scripts. You could try scraping wikipedia - http://en.wikipedia.org/wiki/Wikipedia:Quick_index. I reckon you might find a few more there.
I came across this same question awhile ago, i can’t seem to find the URL, but someone found a longer word. It is abit of a stretch, but that’s the beauty of the English language, who says they’re wrong!
Imagine you keep pet raccoons. Now if you did, where might you put them? well possibly in a nook. That would make you, the keeper of those nooks, hence a Raccoonnookkeeper.
That’s 5 sets of double letters. I think you’ll be hard pressed to beat that or find anyone who agrees it is a real word.