What's the difference between "Ever since" and "Since then"

In this video, Alisha answers 5 questions. - I would like to know the meaning of the expression "every other day." Can I also say "every other week/year/hour/minute?" - When I meet a person that tries to speak a language with me that I don't understand, what should I say in English to respond? - What is the difference between "dying to" and "vying for," and how do we use them properly? - Hung or Hanged? Snuck or Sneaked? - Could you please explain the differences between "ever since" and "since then"?