The Bangla writing system, like many other Indic scripts, is descended from the ancient Brahmi script. These scripts are often referred to as alphasyllabic since, although they are alphabetic with distinct signs for consonants and vowels, the basic element of Indic writing is the syllable.
Perhaps, the most complex aspect of writing Bengali and several other Indic scripts is probably the shaping of consonant conjuncts. These occur when two or more consonants characters join together forming a compound character. It is normal, in the writing of such Indian languages, for such combinations to form conjunct ligatures that they often depart radically from the shape of the original consonant characters. It is this aspect of Indic scripts that pose a great challenge to typography as well as their automatic recognition. In the below, a few examples of joining two consonant characters (same or different) of Bangla forming a compound character are shown.
E + O = k ; O + O = v ; b + O = r
Ka + Tta = Ka_tta Tta + Tta = Tta_tta Ssa + Tta = Ssa_tta
As seen from the above, part of a consonant character or its some modified shape is often used to form a compound character. Due to the presence of such compound characters the total number of different symbols in the Bangla character set exceeds the mark 500. In fact, initially, more than five hundred typing letters were required, but the number had been gradually reduced. Even today, the existing Bengali code of signs in the foundry type consists of 448 to 536 characters. Lino-type provides for 292 characters of which 260 are good enough for the ordinary job. Monotype composition provides for 319 characters.