In traditional music theory, most countries in the world use the solfège naming convention Do–Re–Mi–Fa–Sol–La–Si, including for instance Italy, Portugal, Spain, France, Poland, Romania, most Latin American countries, Greece, Bulgaria, Turkey, Russia, and all the Arabic-speaking or Persian-speaking countries. However, in English- and Dutch-speaking regions, pitch classes are typically represented by the first seven letters of the Latin alphabet (A, B, C, D, E, F and G). A few European countries, including Germany, adopt an almost identical notation, in which H substitutes for B (see below for details). In Indian music the Sanskrit names Sa–Re–Ga–Ma–Pa–Dha–Ni (सा-रे-गा-मा-पा-धा-नि) are used, as in Telugu Sa–Ri–Ga–Ma–Pa–Da–Ni (స–రి–గ–మ–ప–ద–ని), and in Tamil (ச–ரி–க–ம–ப–த–நி). Byzantium used the names Pa–Vu–Ga–Di–Ke–Zo–Ni (πΑ—Βου—Γα—Δι—κΕ—Ζω—νΗ).
Source: Musical note – Wikipedia