I don't speak Italian/German/French.  How will I ever understand what is going on?

We project English translations (called supertitles) above the stage while the singers are performing (even when they're performing in English), so you can always follow along. Just like surtitles in foreign films, except they're above the action, not below it. (And we don't have that whole "actor getting half way through a speech before the sound starts up out of sync" thing going on.)

Unlike foreign films, opera singers often repeat the same line over and over - for effect or to carry the music along.

And honestly - I like pop / rock / punk / folk / jazz music. Half the time I have no idea what they're saying either, but I still love the music and understand the emotion. That's what opera is all about. And the sets, costume, story and acting make it easy to follow along as well. (As a matter of fact, back in the "old days" that's how people managed it - they read a summary of the story ahead of time and then relied on the music and acting to following along with the plot.)