No, you do not need to learn a foreign language to teach abroad. There are some exceptions depending on the type of school you want to teach and the country, you need to speak Spanish to teach in Spanish public schools for example, but you don’t need to know the language to teach at a language centre.
Most schools will actually ask you not to speak the local language in class, However, students to find it entertaining that you know a word or two.
Outside of the classroom it is best to adapt into the culture that you are living and life will be a lot easier for you if you can get along with the locals. And a lot of schools will offer free language lessons. We have posted a few links on the resources page to where you can start learning the language before you leave.