I had noticed the increasing use of Mandarin Chinese in New York City’s Chinatowns, but this article says that this is true even of San Francisco:

A gradual shift from Cantonese, a dialect spoken in southern China, to China’s official language has been taking place in America’s Chinese communities –even in San Francisco’s Chinatown, long a bastion of Cantonese speakers.

… Statistics document the shift: A 1986 consumer survey found that almost 70 percent of Chinese households in the San Francisco area spoke Cantonese; 19 percent spoke Mandarin. A survey last year showed the divide narrowing to 53 percent Cantonese and 47 percent Mandarin, according to a study for KTSF, a television station that devotes most of its programming to Asian-language shows.

The trend is similar in Los Angeles and New York, the nation’s two other major Chinese markets, said Saul Gitlin of Kang & Lee Advertising in New York. Ten or 15 years ago, Mandarin would have been very, very small,” he said.

What the article doesn’t discuss, and I would be interested in knowing, is how Chinese language learning trends of Chinese immigrants are changing.