wait i always just assumed they knew each other! so the show just happened to cast the two of them and they just happened to be cousins? im sorry thats just crazy! --- Doctor Who is crazy. Amy and little Amy are cousins
Quite possibly my favorite scene with Doctor Donna =) I love her because for the first time 10 can have a companion who isn't falling in love with him. It took me a while to get over Rose Tyler but I really loved Donna Noble
Captain Jack has an American accent. They are British because the TARDIS translates the language into what the companion/viewers understand. When translating to English, the default accent is British, for some reason.