A self-enumerating sentence, also known as an autogram, is a sentence whose text consists solely of the enumeration of its letter content. The answer to the question whether such sentence exists in English was given by Lee Sallows, and was first published in Scientific American in Jan 1982:
Only the fool would take trouble to verify that his sentence was composed of ten a's, three b's, four c's, four d's, forty-six e's, sixteen f's, four g's, thirteen h's, fifteen i's, two k's, nine l's, four m's, twenty-five n's, twenty-four o's, five p's, sixteen r's, forty-one s's, thirty-seven t's, ten u's, eight v's, eight w's, four x's, eleven y's, twenty-seven commas, twenty-three apostrophes, seven hyphens and, last but not least, a single!
This remarkable sentence counts not only its own letters, but also its punctuation marks, although it does fails to enumerate three letters of the alphabet (j, q, and z). Sallows went on to devise a "pangram machine" – a computer purpose-built to search for sentences of this type. Among its many successes was:
This pangram lists four a's, one b, one c, two d's, twenty-nine e's, eight f's, three g's, five h's, eleven i's, one j, one k, three l's, two m's, twenty-two n's, fifteen o's, two p's, one q, seven r's, twenty-six s's, nineteen t's, four u's, five v's, nine w's, two x's, four y's, and one z