The Burmese alphabet consists of 33 letters and 12 vowels, and is written from left to right. It requires no spaces between words, although modern writing usually contains spaces after each clause to enhance readability. Characterized by its circular letters and diacritics, the script is an abugida, with all letters having an inherent vowel .The consonants are arranged into six consonant groups based on articulation, like other Brahmi scripts. Tone markings and vowel modifications are written as diacritics placed to the left, right, top, and bottom of letters.
The development of the script followed that of the language, which is generally divided into Old Burmese, Middle Burmese and modern Burmese. Old Burmese dates from the 11th to the 16th century (Pagan and Ava dynasties); Middle Burmese from the 16th to the 18th century (Toungoo to early Konbaung dynasties); modern Burmese from the mid-18th century to the present. Orthographic changes followed shifts in phonology rather than transformations in Burmese grammatical structure and phonology, which has not changed much from Old Burmese to modern Burmese.
Written Burmese dates to the early Pagan period. The script was developed from either the Mon script in 1058 or the Pyu script in the 10th century. (Both Mon and Pyu scripts are derivatives of the Brāhmī script.) Burmese orthography originally followed a square format but the cursive format took hold from the 17th century when popular writing led to the wider use of palm leaves and folded paper known as parabaiks. Much of the orthography in written Burmese today can be traced back to Middle Burmese. Standardized tone marking was not achieved until the 18th century. From the 19th century onward, orthographers created spellers to reform Burmese spelling, because ambiguities arose over spelling sounds that had been merged. During colonial rule under the British, Burmese spelling was standardized through dictionaries and spellers. The latest spelling authority, named the Myanma Salonpaung Thatpon Kyan, was compiled in 1978 at the request of the Burmese government.