Punctuation vowel of the word. Arabic, Urdu, and Persian—written from right to left—use a reversed question mark: , and a reversed comma: . This is a modern innovation; pre-modern Arabic did not use punctuation. Hebrew, which is also written from right to left, uses the same characters as in English, and . Originally, Sanskrit had no punctuation. In the 17th century, Sanskrit and Marathi, both written using Devanagari, started using the vertical bar to end a line of prose and double vertical bars in verse. Punctuation was not used in Chinese, Japanese, and Korean writing until the adoption of punctuation from
That that is is that that is not is not is that it it is That that is is that that is not is not is that it it is That that is is that that is not is not is that it it is is an English word sequence demonstrating syntactic ambiguity. It is used as an example illustrating the importance of proper punctuation. The sequence can be understood as any of four grammatically-correct sequences, each with at least four discrete sentences, by adding punctuation: The first two relate a simple philosophical proverb in the style of Parmenides that all that is, is, and that anything that does not exist does not. The phrase