What is Naturalization Act Of 1906?

Legal Definition
The Naturalization Act of 1906 was an act of the United States Congress signed into law by Theodore Roosevelt that revised the law from 1870 and required immigrants to learn English in order to become naturalized citizens. The bill was passed on June 29, 1906, and took effect September 27, 1906. It was repealed and replaced by the Nationality Act of 1940. It was modified by the Immigration Act of 1990.

The legislation established the federal government as the arbiter of naturalization policy. It created the Bureau of Immigration and Naturalization, which provided for the first uniform naturalization laws in the country. Prior to 1906, an alien could be naturalized in any U.S. "court of record." State-level naturalization courts managed proceedings and had varying standards across the country. After September 26, 1906, naturalization could only be done in courts having a seal and a clerk, and exerting universal competence.
-- Wikipedia