Language variant refers to the different forms of a language that exist within a single language family. These variations can be due to differences in geography, social groups, or specific contexts. A language variant might include differences in accent, vocabulary, grammar, or usage. Essentially, it’s how a language can be spoken or written in diverse ways by different groups of people.
A dialect is one type of language variant. It is a variation of a language that is specific to a particular geographical region or a group. It can include differences in pronunciation, vocabulary and grammar. For example, American English and British English differ in various ways. There are many different dialects with other languages of wider communication.