Between 2001 and 2017, there has been a 38% reduction in the number of people who speak the language at home. In 2001 that number rested around 900,000. Now, that number is closer to 550,000.

Among languages that had at least 100,000 U.S. speakers in 2001, no other language saw quite as large of a decrease, Quartz reports.

That drop is likely due in part to a few reasons. One reason is that there are fewer Italian-born residents in the U.S. now than there were 17 years ago.

The drop in Italian immigrants is due in part to increasing prosperity in Italy. The European Union also played a part, because Italians could easily immigrate to the United Kingdom, a rich, English-speaking country closer to their own. The number of Italians in the UK grow more than 70,000 during that 2001-2017 time frame.

Also, Italian immigrants in the U.S. are getting older, and as they pass away, their families are speaking English at home rather than Italian, further lowering those numbers. Many other languages are suffering the same loss.

Those immigrants are coming from other places now though. Telugu is currently the United States’ fastest growing language, followed by Arabic and then Hindi, according to a September 2018 study by the Center for Immigration Studies.

According to the study, in America’s five largest cities, 48 % of residents now speak a language other than English at home. In New York City and Houston it is 49 %; in Los Angeles, it is 59 %; in Chicago, it is 36 %; and in Phoenix, it is 38 %.