Presidential candidates have been running ads in Spanish for years. They run on spanish language television stations.
And before Spanish, it was Yiddish and Italian and German and Polish ......
While legal immigrants may speak and understand English, a large number of them will always be more comfortable in their first language.
Below are World War I era posters put out by the United States Food Administration and aimed at the legal immigrants living in America in 1918. The text says:
"Food will win the war - You came here seeking freedom, now you must help to preserve it - Wheat is needed for the allies - waste nothing."
Here is one in Yiddish for eastern European Jews:
Here is one for the Italians:
Here is one for English-speaking immigrants such as the Irish: