U.S. citizenship is usually derived from U.S. citizen parents, grandparents or through naturalization. Once you become a U.S. Citizen you are given benefits such as the right to vote and have a U.S. Passport.
You may be able to apply for naturalization if you are at least 18 years of age and have been a Lawful Permanent Resident of the U.S. for at least 5 years; OR, if you are filing based on marriage to a U.S. citizen, for at least 3 years after receiving your permanent residency and continue to engage in a bona fide marriage with your U.S. citizen husband or wife; OR have honorable service in the U.S. military for at least one year. (Certain spouses of U.S. citizens and members of the military may be able to file for naturalization sooner than noted above previously.)
To file for citizenship you must: A) be a person of good moral character; B) have a basic knowledge of U.S. history and government; C) have a period of continuous residence and physical presence in the U.S. since becoming a Lawful Permanent Resident; and D) be able to read, write and speak basic English.
The applicant must be physically present in the U.S. at least half of the period required for continuous residence and have three months of consecutive residence in the state they will be filing in.
There are exceptions to the English language requirement for someone who: A) Is 55 years old and has been a permanent resident for at least 15 years; or B) Is 50 years old and has been a permanent resident for at least 20 years; or C) Has a physical or mental impairment that makes them unable to fulfill these requirements.