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Letter (alphabet)

language culture Maturity 11-13 Next article →

A letter is a specific type of grapheme, which is the smallest functional unit in a writing system. Most letters correspond to a phoneme, the smallest unit of sound in spoken language. While they are closely linked, there is rarely a perfect one-to-one match between a single letter and a single sound. In many alphabets, letters are combined to build written words, just as phonemes are combined to build spoken ones. Sometimes, a single sound requires multiple letters working together. These sequences are known as multigraphs. In English, two-letter groups like "ch" or "sh" are called digraphs. Three-letter groups, such as "tch," are called trigraphs.

Typography Line Terms
Typography Line Terms

Writing systems often use different versions of the same letter, known as allographs. Many scripts utilize two main types: uppercase, also called majuscule, and lowercase, or minuscule. These forms represent the same sound but serve different structural roles. Capital letters are typically used for the start of sentences, proper names, titles, or headers. In the German language, for instance, all nouns must begin with a capital letter. The terms "uppercase" and "lowercase" come from the history of printing. Printers kept metal type in wooden drawers called cases. They stored the larger capital letters in the upper case and the smaller letters in the lower case.

Many alphabets also use diacritics, which are marks or accents added to letters. These marks change how a letter is pronounced. While English rarely uses diacritics except in loanwords like "naïve" or names like "Brontë," they are common in many other languages. In modern computing, these marks are often handled as precomposed characters. This allows computers to recognize specific accented letters as single units.

Typography Line Terms
Typography Line Terms

Before modern alphabets, humans used various phonograms to represent sounds. These included verbal pictures for entire words and syllabic systems that represented word articulations. The earliest alphabetic examples appear in Ancient Egypt and Ancient China around 1050 BCE. A major turning point occurred around 1050 BCE with the Phoenician alphabet. The Phoenicians were Semitic workers in Egypt who developed a script of 22 letters. This original script was written and read from right to left.

Translations of Semitic Letters
Translations of Semitic Letters

The evolution of writing continued as the Phoenician script influenced other cultures. The Etruscan and Greek alphabets both emerged from the Phoenician system. The Greek alphabet was revolutionary because it was the first to assign letters to both consonants and vowels. The Latin alphabet, which is the most widely used today, emerged from these earlier traditions. The Roman Empire refined the Latin alphabet starting around 500 BCE. During the fifth and sixth centuries, the development of lowercase letters began to emerge in Roman writing. By the late 7th and early 8th centuries, writing also developed paragraphs, sentences, and clauses.

NAMA Alphabet grec
NAMA Alphabet grec

Letters have a massive influence on modern science, math, and engineering. They are often used as symbols to represent complex ideas or variables. In some systems, letters also function as numerals, such as in Roman numerals. Letters can even be used to name objects based on their physical shapes. Examples include an "A-frame," an "O-ring," or a "U-bend." We also see letters used as abbreviations, such as "G-man" for a government agent. In many scientific fields, specific letters are used to identify rays, such as alpha, beta, and gamma rays.

Venn diagram showing Greek, Latin and Cyrillic letters
Venn diagram showing Greek, Latin and Cyrillic letters

Because letters are used across many different cultures, they often overlap in surprising ways. Some letterforms are homoglyphs, meaning they look identical but represent different sounds. For example, the Latin "H," the Greek "eta," and the Cyrillic "en" look similar but are distinct phonemes. Conversely, different shapes can represent the same sound. The Greek "sigma" and the Cyrillic "es" both represent the /s/ sound. In the digital age, every letter is assigned a unique code point in computer systems. This ensures that a letter typed in one part of the world is understood correctly everywhere else.

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File:NAMA Alphabet grec.jpg
NAMA Alphabet grec.jpg
File:Public documents of the legislature of Connecticut, session (1882) (14763332785).jpg
Public documents of the legislature of...
File:Translations of Semitic Letters.png
Translations of Semitic Letters.png
File:Typography Line Terms.svg
Typography Line Terms.svg
File:Venn diagram showing Greek, Latin and Cyrillic letters.svg
Venn diagram showing Greek, Latin and...
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