Spelling according to Coulmas (1996, 477) is 'The conventions which determine how the graphemes of a writing system are used to write a language'. In English words generally have accepted standard spellings which can vary regionally or nationally. In the sense of a standard, spelling is one of the elements of orthography and a prescriptive element of alphabetic languages.Spellings attempt to transcribe the sounds of the language into alphabetic letters, but phonetic spellings are exceptions in many languages for various reasons. Pronunciation changes over time in all languages, and spelling reforms are irregular in most languages and rare in some. In addition, words from other languages may be adopted without being adapted to the spelling system, non-standard spellings are often adopted after extensive common usage, and different meanings of a word or homophones may be deliberately spelled in different ways to differentiate them visually.The emergence of an accepted standard spelling is a natural phenomenon. Standardized spelling establishes whenever a writing system develops in order to exhibit less variation and streamline written communication.[citation needed]