In Colombia, there are many different dialects and important differences amongst them. Phonetics may vary, but the most interesting fact is the way people treat each other depending on where they live and how they speak.
You should be aware of the fact that in Colombia, there are some local dialects which have different meanings for the same words. There are three main dialects, and each one has local dialects within it. It shouldn’t be a big problem if you speak some Spanish, but when learning, if you know where you are going to in Colombia, ask your teacher to teach you some local expressions or words.
The second person plural (you) is ‘ustedes.’ like in many parts of Latin America. On the Caribbean coast of Colombia, ‘tú’ is used for colloquial situations, and ‘usted’ is more formal. Inland, ‘usted/ustedes’ is used not only in formal situations, but also between members of the same family, children, and friends. In some other places, ‘voseo’ is used.