There are many requirements one has to fulfill to qualify for US citizenship. One such requirement is taking the citizenship test. Your knowledge in the English language and US government and history (Civics) will be tested.
In the English part, your speaking, reading and writing ability will be evaluated during the interview. You will be given three sentences and you should read one sentence clearly and correctly proving that you are able to understand the meaning of the sentence. The interviewing officer will then dictate three sentences and you are required to write at least one sentence correctly. The way you respond to the questions will judge your speaking ability. All these three form the English test and a final decision will be taken based on your performance in all these three areas.
The USCIS has 100 questions in the civics section and you will be tested orally. The interviewer will ask ten questions from those. You will considered to have passed this section if you can answer at least six out of ten questions correctly.
Per US immigration laws, there are a few exceptions for taking the citizenship test. It is unfair to expect elderly persons to take the citizenship test as others do as they may find it quite difficult proving their ability in knowing English or prove their knowledge of the US government. So, certain applicants are exempted from the test considering their old age and also how long they have been lawful permanent residents. Even some applicants with medically determinable physical or mental impairment are exempted from taking the test.
If you are above 50 years of age and been a green card holder for at least 20 years OR if you are above 55 years of age and been a green card holder for at least 15 years, you need not take the English test. But, you still have to take the Civics test but can take it in a language of your own choice. If you are above 65 years of age and been a green card holder for at least 20 years, you need not take the English test. Though you are still required to take the Civics test and can take it in a language of your choice, this test will be an easier version comparatively. You will be asked 10 questions from a list of 25.
If you are requesting a waiver of the English proficiency requirement, make sure you bring an interpreter along with you to the interview. Most of the question/answers remain the same except for a few, such as questions related to the names of officials holding government positions. If you are requesting a waiver based on your health condition, you should file Form N-648 requesting an exception and this has to be filed the N-400 Form.
If you do not pass the English or Civics test, your application will be rejected. In such a case, you can re apply when you think you have enough knowledge in English or Civics to pass the tests.