Context: The endonym is pronounced /kə.təˈɫa/ in the Eastern Catalan dialects, and /ka.taˈɫa/ in the Western dialects. In the Valencian Community, the term valencià (/va.len.siˈa/) is frequently used instead. The names "Catalan" and "Valencian" are two names for the same language. See also status of Valencian below.

Question: Where is Valencia used instead of Catalan?
Answer: Valencian Community

Question: What are Catalan and Valencian the names for?
Answer: the same language

Question: What affect does  different pronunciations in the two areas of Catalan speakers produce?
Answer: dialects