Sound change refers to the systematic alteration of phonetic sounds in a language over time. This can occur due to various factors, including social interaction, geographical movement, and language contact. As communities evolve, their speech patterns may shift, leading to new pronunciations and the emergence of dialects. There are two main types of sound change: phonetic change, which affects the actual sounds produced, and phonological change, which alters the rules governing sound patterns. These changes can result in the development of new languages or dialects, illustrating the dynamic nature of human communication.