M is the thirteenth letter

Letter (alphabet)

A letter is a grapheme in an alphabetic system of writing, such as the Greek alphabet and its descendants. Letters compose phonemes and each phoneme represents a phone in the spoken form of the language....

 of the basic modern Latin alphabet

Basic modern Latin alphabet

The International Organization for Standardization basic Latin alphabet consists of the following 26 letters:By the 1960s it became apparent to the computer and telecommunications industries in the First World that a non-proprietary method of encoding characters was needed...

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The letter M is derived from the Phoenician

Phoenician alphabet

The Phoenician alphabet, called by convention the Proto-Canaanite alphabet for inscriptions older than around 1050 BC, was a non-pictographic consonantal alphabet, or abjad. It was used for the writing of Phoenician, a Northern Semitic language, used by the civilization of Phoenicia...

 Mem

Mem

Mem is the thirteenth letter of many Semitic abjads, including Phoenician, Aramaic, Hebrew and Arabic...

, via the Greek

Greek alphabet

The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...

 Mu

Mu (letter)

Carlos Alberto Vives Restrepo is a Grammy Award and three-time Latin Grammy Award winning-Colombian singer, composer and actor.-Biography:...

 (Μ, μ). Semitic

Semitic

In linguistics and ethnology, Semitic was first used to refer to a language family of largely Middle Eastern origin, now called the Semitic languages...

 Mem probably originally pictured water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

. It is known that Semitic people working in Egypt c. 2000 BC borrowed a hieroglyph for "water" that was first used for an alveolar nasal

Alveolar nasal

The alveolar nasal is a type of consonantal sound used in numerous spoken languages. The symbol in the International Phonetic Alphabet that represents dental, alveolar, and postalveolar nasals is , and the equivalent X-SAMPA symbol is n....

 (/n/), because of the Egyptian word for water, n-t. This same symbol became used for /m/ in Semitic, because the word for water began with that sound.

The letter ⟨m⟩ represents the bilabial consonant

Bilabial consonant

In phonetics, a bilabial consonant is a consonant articulated with both lips. The bilabial consonants identified by the International Phonetic Alphabet are:...

 sound, m, in Classical languages as well as the modern language

Language

Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

s.