section_path: Writing system
section_name: Writing system
paragraph_text: Writing system
  
  The Bengali-Assamese script is an abugida, a script with letters for consonants, with diacritics for vowels, and in which an inherent vowel (অ ô) is assumed for consonants if no vowel is marked. The Bengali alphabet is used throughout Bangladesh and eastern India (Assam, West Bengal, Tripura). The Bengali alphabet is believed to have evolved from a modified Brahmic script around 1000 CE (or 10th–11th century). It is a cursive script with eleven graphemes or signs denoting nine vowels and two diphthongs, and thirty-nine graphemes representing consonants and other modifiers. There are no distinct upper and lower case letter forms. The letters run from left to right and spaces are used to separate orthographic words. Bengali script has a distinctive horizontal line running along the tops of the graphemes that links them together called মাত্রা matra.
  
  Since the Bengali script is an abugida, its consonant graphemes usually do not represent phonetic segments, but carry an "inherent" vowel and thus are syllabic in nature. The inherent vowel is usually a back vowel, either as in মত "opinion" or, as in মন "mind", with variants like the more open. To emphatically represent a consonant sound without any inherent vowel attached to it, a special diacritic, called the hôsôntô (্), may be added below the basic consonant grapheme (as in ম্). This diacritic, however, is not common and is chiefly employed as a guide to pronunciation. The abugida nature of Bengali consonant graphemes is not consistent, however. Often, syllable-final consonant graphemes, though not marked by a hôsôntô, may carry no inherent vowel sound (as in the final ন in মন or the medial ম in গামলা).
  
  A consonant sound followed by some vowel sound other than the inherent is orthographically realised by using a variety of vowel allographs above, below, before, after, or around the consonant sign, thus forming the ubiquitous consonant-vowel typographic ligatures. These allographs, called কার kar, are diacritical vowel forms and cannot stand on their own. For example, the graph মি represents the consonant followed by the vowel, where is represented as the diacritical allograph ি (called ই-কার i-kar) and is placed before the default consonant sign. Similarly, the graphs মা, মী, মু, মূ, মৃ, মে, মৈ, মো and মৌ represent the same consonant ম combined with seven other vowels and two diphthongs. In these consonant-vowel ligatures, the so-called "inherent" vowel is first expunged from the consonant before adding the vowel, but this intermediate expulsion of the inherent vowel is not indicated in any visual manner on the basic consonant sign ম.
  
  The vowel graphemes in Bengali can take two forms: the independent form found in the basic inventory of the script and the dependent, abridged, allograph form (as discussed above). To represent a vowel in isolation from any preceding or following consonant, the independent form of the vowel is used. For example, in মই "ladder" and in ইলিশ "Hilsa fish", the independent form of the vowel ই is used (cf. the dependent form ি). A vowel at the beginning of a word is always realised using its independent form.
  
  In addition to the inherent-vowel-suppressing hôsôntô, three more diacritics are commonly used in Bengali. These are the superposed chôndrôbindu (ঁ), denoting a suprasegmental for nasalisation of vowels (as in চাঁদ "moon"), the postposed ônusbar (ং) indicating the velar nasal (as in বাংলা "Bengali") and the postposed bisôrgô (ঃ) indicating the voiceless glottal fricative (as in উঃ! "ouch!") or the gemination of the following consonant (as in দুঃখ "sorrow").
  
  The Bengali consonant clusters (যুক্তব্যঞ্জন juktôbênjôn) are usually realised as ligatures, where the consonant which comes first is put on top of or to the left of the one that immediately follows. In these ligatures, the shapes of the constituent consonant signs are often contracted and sometimes even distorted beyond recognition. In the Bengali writing system, there are nearly 285 such ligatures denoting consonant clusters. Although there exist a few visual formulas to construct some of these ligatures, many of them have to be learned by rote. Recently, in a bid to lessen this burden on young learners, efforts have been made by educational institutions in the two main Bengali-speaking regions (West Bengal and Bangladesh) to address the opaque nature of many consonant clusters, and as a result, modern Bengali textbooks are beginning to contain more and more "transparent" graphical forms of consonant clusters, in which the constituent consonants of a cluster are readily apparent from the graphical form. However, since this change is not as widespread and is not being followed as uniformly in the rest of the Bengali printed literature, today's Bengali-learning children will possibly have to learn to recognise both the new "transparent" and the old "opaque" forms, which ultimately amounts to an increase in learning burden.
  
  Bengali punctuation marks, apart from the downstroke । daṛi – the Bengali equivalent of a full stop – have been adopted from Western scripts and their usage is similar.
  
  Unlike in Western scripts (Latin, Cyrillic, etc.) where the letter forms stand on an invisible baseline, the Bengali letter-forms instead hang from a visible horizontal left-to-right headstroke called মাত্রা matra. The presence and absence of this matra can be important. For example, the letter ত tô and the numeral ৩ "3" are distinguishable only by the presence or absence of the matra, as is the case between the consonant cluster ত্র trô and the independent vowel এ e, also the letter হ hô and Bengali Ôbogroho ঽ (~ô) and letter ও o and consonant cluster ত্ত ttô. The letter-forms also employ the concepts of letter-width and letter-height (the vertical space between the visible matra and an invisible baseline).
  
  There is yet to be a uniform standard collating sequence (sorting order of graphemes to be used in dictionaries, indices, computer sorting programs, etc.) of Bengali graphemes. Experts in both Bangladesh and India are currently working towards a common solution for this problem.