Linguistic diversity in the US continues to expand. The share of people who speak English at home fell from 78.4% in 2016 to 78.1% in 2018, according to recently released data from the US Census.

In terms of total speakers, the fastest-growing non-English language was Spanish, with almost one million more in 2018 than 2016, an increase of 2.4% over the period.

Yet in terms of speed of growth, most of the the US’s fastest-growing languages come from South Asia. Of the 10 fastest growing, six are South Asian and three are from Africa. The one outlier is “Pennsylvania Dutch/Yiddish,” whose growth is a result of the fast-growing Amish population.

The swift proliferation of South Asian and African languages is representative of immigration trends. New immigrants from Asia and Africa make up an increasing share of the US foreign-born population compared to those from Latin America—mostly due to a drop off in the number of immigrants from Mexico.

Another reason these languages have grown so quickly is that they were coming from a relatively small base. Fewer than a million people in the US spoke each of the 10 fastest-growing languages in 2016. As a result, even a small influx of Tamil speakers can mean a dramatic percentage increase.

Language data affords a unique glimpse into the regional origins of immigrants from huge multilingual countries like India. The faster growth of languages spoken in the southern parts of India, like Malayalam and Tamil, compared to those spoken in the north of the country, like Hindi, shows exactly which regions Indian immigrants to the US are coming from.