Question

the main, or central, idea of the passage is the high incidence of deafness on marthas vineyard led to the development of a bilingual society. how does the detail in bold develop the main idea? while researching marthas vineyard, an island off the coast of massachusetts, anthropologist nora groce made a remarkable discovery. she learned that from the 1600s until the early 1900s, almost all the residents of two towns on the island—west tisbury and chilmark—were fluent in sign - language. during these years, the towns had an unusually high population of deaf people, due to a form of hereditary deafness that ran in many marthas vineyard families. consequently, a bilingual society developed. the islanders didnt attend special sign - language classes; they simply learned the language as they grew up. one of the most interesting aspects of the phenomenon was that, in the absence of language barriers, deafness was not perceived as a disability. as one vineyarder explained to groce, deaf people were seen as just like everyone else. it illustrates how natural and widespread the use of sign language was on the island. it explains two different ways that one can learn sign language.

Explanation:

The bold - faced detail shows that from the 1600s to the early 1900s, many residents on the island were fluent in sign language. This indicates that the use of sign language was natural and widespread on Martha's Vineyard. It doesn't focus on two different ways to learn sign language but rather on the prevalence of sign - language use.

Answer:

It illustrates how natural and widespread the use of sign language was on the island.