Right pedal - The loud one. Also known as the "forte" or sustain pedal, it prevents dampers from descending on the piano strings, resulting in a rich, sustained chord peal.
Left pedal - The soft one or "una corda." A single piano note is normally created from two or three piano strings tuned in unison. This pedal shifts the hammer so that it hits only one or two strings, resulting in a more muted sound. Hence, "una corda" or "one string."
Middle pedal - The "sostenuto." This pedal selectively sustains notes, so that certain notes can ring out while others fade normally. It is usually found only on grand pianos.
Hope that helps
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