Katherine Heigl was born in Washington, D.C., United States of America at Columbia Hospital for Women, which is why she is well aware of American languages, including primary, as well as local.
Actress Katherine Heigl Speaks Languages Fluently
Katherine Heigl is very fluent in English, which is her official language, and most American people know English very well in the United States. Her father is of Irish and German ancestry (including Swiss-German), and her mother is of German descent. So, it is a strong possibility that she also understands and speaks both languages, German and French.