An accent or dialect is the way that people talk in different parts of the world or even within the same country. Just like how you might say words differently than your friend who lives in a different place, people from different parts of the world might speak the same language but with different accents or dialects.
For example, someone from England might say "bath" differently than someone from America. Someone from Australia might say "mate" more often than someone from Canada.
Sometimes accents and dialects can be hard to understand if you're not used to hearing them, but they are all part of what makes languages interesting and fun!