Deafblind people communicate in many different ways determined by the nature of their condition, the age of onset, and what resources are available to them. For example, someone who grew up deaf and experienced vision loss later in life is likely to use a sign language (in a visually modified or tactile form).
To burn someone's bridges is too forget about them. Ryan built bridges, meaning he still might want to come back to her. He is telling her to burn them, because he can't seem to do it himself. It isn't easy for him to forget her, and hes asking for her help.
The definition of a burn is a place or area destroyed or damage by fire. An example of a burn is a mark on one's finger from touching a flame. Burn means to be on fire, to be destroyed by fire or to give off light. An example of to burn is when a pile of oily rags catches on fire. An example of to burn is to be injured after sticking your hand in a fire. An example of to burn is for a candle to create a flame.