You can study abroad even if you only know to speak English and you won’t be limited to English-speaking countries like England, USA or Australia, either. While some programs have a language prerequisite and some may only offer courses in the host country’s language, there are study abroad programs available in English all over the world. If you feel intimidated about the pending language challenges, you can also actively pursue a study abroad program that is taught only in English.
Language will not be a barrier for you. Knowing only English is enough most of the times. After a few days, you may proceed with learning the local language if you wish. But overall, you can apply to such countries where English is not the first language.