Hindi is written in the Devanagari script, an abugida. An abugida is a segmental writing system in which consonant-vowel sequences are written as a unit; each unit is based on a consonant letter, and vowel notation is secondary. Devanagari is based on the ancient Brāhmī script, used in the Indian subcontinent. It was developed in ancient India from the 1st to the 4th century CE.
The Devanagari script, composed of 47 primary characters including 14 vowels and 33 consonants, is the fourth most widely adopted writing system in the world, being used for over 120 languages. The ancient Nagari script for Sanskrit had two additional consonantal characters.
The letter order of Devanagari, like nearly all Brahmic scripts, is based on phonetic principles that consider both the manner and place of articulation of the consonants and vowels they represent. This arrangement is usually referred to as the varṇamālā “garland of letters”. The format of Devanagari for Sanskrit serves as the prototype for its application, with minor variations or additions, to other languages.
The standard Hindi alphabet, as agreed by the Government of India, has 11 vowels and 35 consonants. However, the traditional Hindi alphabet is considered to be made of 13 vowels and 33 consonants. The letters अं [am] and अः [ah] are counted as vowels in traditional Hindi and as consonants in standard Hindi.
In popular and traditional teachings, three extra consonants are used. They are called conjuncts and are a combination of two consonants. This happens when successive consonants with no vowel between them physically join together, for example: क्ष [ksh] is a combination of क and ष, [k] and [sh].
The orthography of the Devanagari script reflects the pronunciation of the language. However, unlike for Sanskrit, Devanagari is not entirely phonetic for Hindi, especially failing to mark schwa dropping in spoken Standard Hindi.
Unlike the Latin or Cyrillic script, the Devanagari script has no concept of letter case. It is written from left to right, has a strong preference for symmetrical rounded shapes within squared outlines, and is recognizable by a horizontal line that runs along the top of full letters.