With regards to just language, how did Shakespeare keep readers engaged with Romeo and Juliet, even though they know what is going to happen? With...

Although we know what is going to happen, we dont know exactly how it
will happen.  Shakespeares beautiful and hilarious speeches keep us
engaged.

There is a lot of beautiful language in the play. 
Some of it is very romantic and enthralling.  Consider s first encounter.

Good pilgrim, you do wrong your hand too much,

Which mannerly devotion shows in this;

For saints have hands that
pilgrims hands do touch,

And palm to palm is holy palmers kiss.(105) (Act 1,
Scene 5, p. 32)

This exchange is part of the lovely
conversation betweenand, which some scholars have considered...