They tried to choose the most understandable signs from diverse sign languages to make the language easy to learn for not only the deaf but for interim management and an ordinary person.[2][3] IS interpreter Bill Moody noted in a 1994 paper that the vocabulary used in conference settings is largely derived from the sign languages of the Western world and is less comprehensible to those from African or Asian sign language backgrounds.[16] A 1999 study by Bencie Woll suggested that IS signers often use a large amount of vocabulary from their native language,[5] choosing sign variants that would be more easily understood by a foreigner.[18] In contrast, Rachel Rosenstock notes that the vocabulary exhibited in her study of International Sign was largely made up of highly iconic signs common to many sign languages: