8 U.S.C. § 1423

(a) No person except as otherwise provided in this subchapter shall hereafter be naturalized as a citizen of the United States upon his own application who cannot demonstrate— (1) an understanding of the English language, including an ability to read, write, and speak words in ordinary usage in the English language: Provided , That the requirements of this paragraph relating to ability to read and write shall be met if the applicant can read or write simple words and phrases to the end that a reasonable test of his literacy shall be made and that no extraordinary or unreasonable condition shall be imposed upon the applicant; and (2) a knowledge and understanding of the fundamentals of the history, and of the principles and form of government, of the United States. (b) (1) The requirements of subsection (a) shall not apply to any person who is unable because of physical or developmental disability or mental impairment to comply therewith. (2) The requirement of subsection (a)(1) shall not apply to any person who, on the date of the filing of the person’s application for naturalization as provided in section 1445 of this title , either— (A) is over fifty years of age and has been living in the United States for periods totaling at least twenty years subsequent to a lawful admission for permanent residence, or (B) is over fifty-five years of age and has been living in the United States for periods totaling at least fifteen years subsequent to a lawful admission for permanent residence. (3) The Attorney General, pursuant to regulations, shall provide for special consideration, as determined by the Attorney General, concerning the requirement of subsection (a)(2) with respect to any person who, on the date of the filing of the person’s application for naturalization as provided in section 1445 of this title , is over sixty-five years of age and has been living in the United States for periods totaling at least twenty years subsequent to a lawful admission for permanent residence.