Accordions are a part of the box-shaped musical instruments of the
bellows-driven free-reed aerophone type, colloquially referred to as
a squeezebox. A person who plays the accordion is called an
accordionist. The concertina and bandoneón are related; the
harmonium and American reed organ are in the same family.
The instrument is played by compressing or expanding the bellows while pressing buttons or keys, causing valves, called pallets, to open, which allow air to flow across strips of brass or steel, called reeds that vibrate to produce sound inside the body. The performer normally plays the melody on buttons or keys on the right-hand manual, and the accompaniment, consisting of bass and pre-set chord buttons, on the left-hand manual. The accordion is widely spread across the world.
For beginners though one must be careful as children and teens or adults will need to start off with different sizes due to the difference in hand and general body size. Children should start with the lowest number of bass buttons, 12 bass and 25 treble keys. Thus for beginners it would be beneficial to get guidance from a professional who will train you in handling your instrument which is very crucial since it requires your left arm to move horizontally and vertically, while your right hand will only move vertically.