R, or r, is the eighteenth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ar (pronounced ), plural ars, or in Ireland or . The letter is the eighth most common letter in English and the fourth-most common consonant (after , , and ). The letter is used to form the ending "-re", which is used in certain words such as centre in some varieties of English spelling, such as British English. Canadian English also uses the "-re" ending, unlike American English, where the ending is usually replaced by "-er" (center). This does not affect pronunciation. Name The name of the letter in Latin was (), following the pattern of other letters representing continuants, such as F, L, M, N and S. This name is preserved in French and many other languages. In Middle English, the name of the letter changed from to , following a pattern exhibited in many other words such as farm (compare French ferme) and star (compare German Stern). In Hiberno-English the letter is called or , somewhat similar to oar, ore, orr. The letter R is sometimes referred to as the (literally 'canine letter', often rendered in English as the dog's letter). This Latin term referred to the Latin R that was trilled to sound like a growling dog, a spoken style referred to as ('dog voice'). A good example of a trilled R is in the Spanish word for dog, perro. In William Shakespeare's Romeo and Juliet, such a reference is made by Juliet's nurse in Act 2, scene 4, when she calls the letter R "the dog's name". The reference is also found in Ben Jonson's English Grammar. History Antiquity The modern letter “r” is believed to derive from the original Semitic letter, such as the Hebrew letter “reish” (ר). It was used for by Semites because in their language, the word for "head" was rêš (also the name of the letter). It developed into Greek 'Ρ' (rhô) and Latin R. The descending diagonal stroke develops as a graphic variant in some Western Greek alphabets (writing rho as ), but it was not adopted in most Old Italic alphabets; most Old Italic alphabets show variants of their rho between a "P" and a "D" shape, but without the Western Greek descending stroke. Indeed, the oldest