The Roman Phonetic Alphabet for English is a system based on the Extended Basic Roman spelling of English. It includes two pairs of stress marks which disambiguate words which share the same spelling but have different meanings. This is to get a one-to-one phoneme (sound)–grapheme (spelling) correspondence. The system has certain similarities to the systems of the NBC Handbook of Pronunciation, the Carnegie Mellon version of Arpabet alphabet, and the World Book Dictionary.