All applicants who apply for naturalization must pass an English language and American civics exam in order to become US citizens. However, the US government and the USCIS acknowledge that for some persons with developmental or physical challenges, it may be difficult to prepare for and to pass such an exam. If you have a mental impairment, developmental disability, or physical disability that you believe would not allow you to pass the citizenship exam, you may file USCIS Form N-648 (Medical Certification for Disability Exceptions), which must be completed by a licensed clinical psychologist or qualified licensed physician in order to waive the examination requirement. Form N-648 must be submitted with Form N-400 at the time of the application of naturalization.