In the Old English language that was spelled þæt. It was also abbreviated as a letter Thorn, þ, with the ascender crossed ( ). In Middle English the letter Ash, æ, was replaced with the letter a, so that that was spelled þat, or sometimes þet. The ascender of the þ was reduced (making it similar to the Old English letter Wynn, ƿ), which necessitated writing a small t above the letter to abbreviate the word that ( ). In latter Middle English and Early Modern English the þ evolved into a y shape, so that the word was spelled yat (although the spelling with a th replacing the þ was starting to become more popular) and the abbreviation for that was a y with a small t above it ( ). This abbreviation can still be seen in reprints of the 1611 edition of the King James Version of the Bible in places such as 2 Corinthians 13:7.
He said that that 'that' that that man used was wrong.Or six times:
He said that that 'that' that that 'that' modified was wrong.Or seven times:
Did the editor know that, that that 'that' that that 'that' followed was redundant?
The same thing is possible with the German equivalent of that 'das', with the exception that 'das' is sometimes written 'dass' (or older 'daß') to make it easier to read, though it is pronounced the same way.
The pattern can be repeated indefinitely and retain its grammatical correctness:
Did you know that that 'that' that that 'that' that that 'that' that that 'that'...
Other patterns of grammatically correct multiple consecutive occurrences are also possible. For example:
That that is is that that that that is not is not.