The answer is : Oh, she does teach the torches to burn bright!
Metaphor is a form of literature technique that contain an implied comparison between a certain meaning with another.
By saying she doth teach the torches to burn bright!, Rome basically saying that Juliet is a source of light, like a star, against the darkness his life.
First person pointer view is the answer
Plurilingualism is a situation wherein a person who has competence in more than one language can switch between languages from one language to another and vice versa