The main language of Valencia is Spanish; however, there are many dialects, such as Valenciano, which the majority of the population speaks. Public signage is written in Valenciano as the primary language followed by Spanish. English is common in Valencia, as well; however, it shouldn't be assumed that people will speak it here.
In Spain the currency is the euro. One euro has slightly more value than the U.S. dollar; however, the ratio is approximately 1:1.
The price of a bottle of water will depend on the area of the city that you are in, but the average cost would be between $0.75 and $1.00.
We ate out in the city center at a restaurant called VIPS, where I ordered a chicken poke bowl. It featured carrots, peppers, rice, peanuts and broccoli. It was absolutely delicious.