Naturalization is the legal process by which a person who is not a national of a country acquires citizenship of that country after birth. It typically involves an application, meeting specific requirements such as a minimum period of legal residence, good moral character, knowledge of the country's language and culture, and taking an oath of allegiance. The exact rules and procedures vary by country
. For example, in the United States, naturalization requires lawful permanent residence for at least five years (or three years if married to a U.S. citizen), continuous physical presence, good moral character, and attachment to the U.S. Constitution. Applicants must file a formal application and pass a citizenship test before taking an oath of allegiance
. In Germany, naturalization usually requires habitual and legal residence for five years, proof of identity and citizenship, and passing a naturalization test demonstrating knowledge of the legal and social system
. Naturalization grants the individual the full rights and responsibilities of citizenship, but some countries may require renouncing previous citizenships. Authorities may also have discretion to deny or revoke naturalization under certain conditions
. In summary, naturalization is the formal legal process by which immigrants become citizens of a country, distinct from citizenship acquired automatically at birth
