both consonants and vowels. The term alphasyllabary was suggested for the Indic scripts in 1997 by William Bright, following South Asian linguistic usage, to convey the idea that "they share features of both alphabet and syllabary." General description The formal definitions given by Daniels and Bright for abugida and alphasyllabary differ; some writing systems are abugidas but not alphasyllabaries, and some are alphasyllabaries but not abugidas. An abugida is defined as "a type of writing system whose basic characters denote consonants followed by a particular vowel, and in which diacritics denote other vowels". (This 'particular vowel' is referred to as the inherent or implicit vowel, as opposed to the explicit vowels marked by the 'diacritics'.) An alphasyllabary is defined as "a type of writing system in which the vowels are denoted by subsidiary symbols not all of which occur in a linear order (with relation to the consonant symbols) that is congruent with their temporal order in speech". Bright did not require that an alphabet explicitly represent all vowels. ʼPhags-pa is an example of an abugida that is not an alphasyllabary, and modern Lao is an example of an alphasyllabary that is not an abugida, for its vowels are always explicit. This description is expressed in terms of an abugida. Formally, an alphasyllabary that is not an abugida can be converted to an abugida by adding a purely formal vowel sound that is never used and declaring that to be the inherent vowel of the letters representing consonants. This may formally make the system ambiguous, but in practice this is not a problem, for then the interpretation with the never-used inherent vowel sound will always be a wrong interpretation. The actual pronunciation may be complicated by interactions between the sounds apparently written just as the sounds of the letters in the English words wan, gem and war are affected by neighbouring letters. The fundamental principles of an abugida apply to words made up of consonant-vowel (CV) syllables. The syllables are written as a linear sequences of the units of the script. Each syllable is either a letter that represents the sound of a consonant and its inherent vowel or a letter modified to indicate the vowel, either by means of diacritics or by changes in the form of the letter itself. If all modifications are by diacritics and all diacritics follow the direction of the writing of the letters, then