MASON CITY, Iowa—When Aileen Prabhakaran took a job in Iowa, the young doctor from India expected a land of icy winters, cultivated fields and quiet living. One thing the 31-year-old, whose entire schooling was in English, didn't expect: a communication barrier.

Then last year, she enrolled in a cultural-competency course at the hospital where she is a resident in family medicine. "It enabled me to understand Iowa and Iowans better," she says.

The...