Carla, Gescab doesn't have an English version.
The Salerno schedule isn't posted on that site because boats aren't currently running. Otherwise, they're pretty easy to figure out. If there's a word or phrase you simply can't make out, use on online translator; it may not be perfect but it's usually close enough to grasp the meaning.
For instance, look at the Sorrento- Capri schedule? "Giornaliero" means the boat runs at that time every day. "Feriale" is weekdays only.
"Ordinario su corse OSP" means it's a required public service run, and "Ordinario" is an extra run (not required of the line) so ticket prices are a little bit higher. "Bagagli" is a luggage charge. Looks like there'es also a 1.50 PP euro surcharge. "Solo Andata" is one way, and "Andata e Ritorno" is round trip.
Anyway, you get the idea?