Meaningful English sentences containing very few distinct letters

An English pangram is a sentence that contains each of the 26 letters used in English, the classic example being `the quick brown fox jumps over the lazy dog.' What I am looking for is precisely the opposite. I am looking for meaningful English phrases or sentences that contain very few distinct letters, preferably 8 or less.

A small example is the computer science phrase `hello world' which is meaningful and contains only 7 distinct letters (h,e,l,o,w,r,d). Is there a repository containing examples of similar phrases, or can Stack Exchange users generate their own?

Why would you want such phrases?

I am mathematician and I plan to teach a group of high school about Huffman codes. A Huffman code is a code for converting letters into binary (0s and 1s). Given a sentence (or passage, or book) the coding is chosen so as to minimize the total number of binary digits needed. So for example, in English the letter E is very frequent and the letter Z is not; one might then assign the letter E the short binary sequence 110, and the letter Z the longer sequence 111100101. That way when you convert a book into binary you will use fewer digits than if, say, you had assigned 111100101 to E and 110 to Z.

In working through examples in class, the tediousness of generating the code is directly proportional to the number of distinct letters contained in the passage one is encoding. Roughly speaking, the fewer letters present, the shorter the code book needs to be. English sentences containing few distinct letters would, for this reason, be great examples to Huffman encode.

Solution 1:

Sounds like a fun lesson you have planned.

The trick here is to find words with repeated letters, and alliteration and assonance help.

Your hello world example had 7 letters, so I created some phrases with less than 7 letters:

1. An assassin sins (4 letters)
2. Eleven elves (5 letters)
3. Free the referee (5 letters)
4. Twitter tweet (5 letters)
5. Catch the cat (5 letters)
6. Hum drum (5 letters)
7. I rent tents (5 letters)
8. Groggy puppy (6 letters)
9. No inhibition (6 letters)
10. Beekeepers keep bees (6 letters)

Here is a resource from professor David Singmaster at puzzlemuseum.com which lists (among other things) words with repeating letters, categorized by word length which might assist you if you want to create any more.

Solution 2:

This one has four distinct letters:

Madam, I'm Adam.

It's also notable because it is a palindrome, and it was also the first sentence uttered by a human being (joke).