how might being unable to speak or understand english affect someones ablity to exercise his or her rights and responsibilities as a citizen?

If a person is unable to understand or speak a language of the place they are residing in, it becomes difficult for them to survive. They will not understand what the locals are telling them and neither will they be able to convey their message to them.

If they do not understand English and they are living in a place where English dominates as a language, they might not be able to speak up if anything wrong or unjust happens to them. They wont know their responsibilities as a citizen and will fail to survive in that area.