language, and accordingly require the development of an enormous vocabulary. They usually achieve this by taking signs ("lexicon") from the local deaf sign language as a base, then adding specially created signs for words and word endings that do not exist in the deaf sign language, often using "initializations", and filling in any gaps with fingerspelling. Thus "Signed English" in America (based on ASL) has a lexicon quite different from "Signed English" in Britain (based on BSL), as well as the Signed Englishes of Ireland, Australasia and South Africa. "Signing Exact English" (SEE2) was developed in the United States in 1969, has also been taught around the world, and is now used in deaf schools in Singapore, and taught in classes by the Singapore Association for the Deaf. Mouth–hand systems Another widespread approach is to visually represent the phonemes (sounds) of an oral language, rather than using signs for the words. These systems are sometimes known as "Mouth Hand Systems" (MHS). An early example was developed in Denmark in 1903 by Georg Forchhammer. Others include the Assisted Kinemes Alphabet (Belgium) and a Persian system developed in 1935 by Jabar Baghtcheban—in addition to the most widespread MHS worldwide, Cued Speech. As the entire set of phonemes for an oral language is small (English has 35 to 45, depending on the dialect), an MHS is relatively easy to adapt for other languages. Cued Speech can be seen as a manual supplement to lipreading. A small number of hand shapes (representing consonants) and locations near the mouth (representing vowels) differentiate between sounds not distinguishable from on the lips; in tonal languages, the inclination and movement of the hand follows the tone. When viewed together with lip patterns, the gestures render all phonemes of the oral language intelligible visually. Cued Speech is not traditionally referred to as a manually coded language; although it was developed with the same aims as the signed oral languages, to improve English language literacy in Deaf children, it follows the sounds rather than the written form of the oral language. Thus, speakers with different accents will "cue" differently. Cued speech has been used to prepare deaf children for hearing aids and cochlear implants by teaching the prospective wearer the oral language's phonemes. By the time the child has received a hearing aid or has been implanted with a cochlear implant, the child does not need such intense auditory training