Language can be defined as a system of arbitrary vocal symbols used by a social group to communicate and express ideas, identities, and emotions. There are many variations within and across languages, including dialects, registers, sociolects, and ethnolects that vary by region, social group, ethnicity, gender, and even individual. Some key types of linguistic variations include dialects, which can differ in vocabulary, grammar and pronunciation depending on geography; sociolects, which vary based on social factors like education and class; and idiolects, an individual's unique way of speaking. Languages exist on spectrums and can be classified based on various social and historical contexts.