Varieties of American Sign Language  American Sign Language (ASL) developed in the United States and Canada, but has spread around the world. Local varieties have developed in many countries, but there is little research on which should be considered dialects of ASL (such as Bolivian Sign Language) and which have diverged to the point of being distinct languages (such as Malaysian Sign Language). The following are sign language varieties of ASL in countries other than the US and Canada, languages based on ASL with substratum influence from local sign languages, and mixed languages in which ASL is a component. Distinction follow political boundaries, which may not correspond to linguistic boundaries. Bolivian Sign Language (Lenguaje de Señas Bolivianas, LSB) is a dialect of American Sign Language (ASL) used predominantly by the Deaf in Bolivia. In 1973, American Sign Language was brought to Bolivia by Eleanor and Lloyd Powlison, missionaries from the United States. An indigenous sign language (or perhaps sign languages) existed before the introduction and adoption of American Sign Language, though it is unknown how widespread or unified it was. The first book of LSB was published in 1992, but more than 90% of the signs were from ASL. Due to research work in the 1990s and 2000s a lot of expressions in LSB were collected by Bolivian Deaf, and education materials for learning LSB or teaching in LSB were published. The dependence on words used in ASL was reduced, but the usage of ASL words still is over 70%. Today LSB is used by more deaf Bolivians than the reported 400 in 1988 in the Ethnologue report, due to the introduction of bilingual education (LSB as primary language and Spanish as secondary language) originally in Riberalta and its adoption to other schools in Bolivia with the support of the Education Ministry of Bolivia and the growing social exchange of the Deaf. In 1988, there were a total of 9 deaf institutions in the country and 46,800 deaf Bolivians. In 2002 there were approximately 25 deaf schools. Costa Rican Sign Language, also known New Costa Rican Sign Language or Modern Costa Rican Sign Language, is the national sign language of Costa Rica's Deaf community. It is used primarily by people born after 1960, and is about 60% cognate with American Sign Language (Woodward 1991, 1992). It is unrelated to two known village sign languages of Costa Rica, Bribri Sign Language and Brunca Sign Language.