Understand
You can talk English in Hesse without a problem, but it's better when you speak slowly, as many people are not confident about their English and do not want to embarrass themselves with a native speaker. In smaller towns and out in the country, it's more likely that you will encounter old people who cannot speak or understand English.
However, as students take English as a second language, you'll find that almost all young people speak English well, albeit possibly accented. Even slightly older people usually do have at least some command of English, and in the cities you should not be surprised to find a 60 year old who speaks English quite well.
You may be surprised at how friendly the people can be, as like most Germans the Hessians are very friendly and nice when you are friendly too.
You can get some good tips on local events and places to visit from the locals if your take the time to ask.
Feel free to try out any German you have--either you'll get what you want, or at the least impress/amuse your victim!
