The ones that come to mind are exclamations:

Boooo! (what a ghost says)

Aaaaah! (an exclamation of discomfort, or pleasure)

Eeeeek! (an exclamation by a terrified woman)

Hmmmm (an exclamation of uncertainty)

There is no standard number of same letters in ones such as the above. There can be three or more of the same letter. As to what is the maximum n

I would really appreciate an answer to this question, as it would help me develop a system that prevents automated password generators from accessing people passwords.

Brrr is another.
Or were you looking for words like overstuffed, which have consecutive letters from the alphabet?

Yes, I mean words like overstuffed with rstu
We can exclude outliers (if there happens to be a word like abcdefghijk)
Words like Aaaaah dont matter and we can also exclude words with no standard spelling as long as they aren't used very often.
Hopefully we can find an answer that includes ~99% of English words.
And I'm also hoping that it would be the same number for the other mos

http://www.fun-with-words.com/word_consecutive_letters.html:
http://mentalfloss.com/article/52926/brain-game-row-three

I don't know if this would solve your problem, but I also f

I just realized I could get a word count there. 178,712 words in "TWL", and 585,052 in "Zinga".