Soo..What's your type?
Generally, accordions are grouped into 4 classifications, namely:
- Piano Accordion – the most popular type especially in the US, meaning more widely accessible compared to the rest. Because of the piano keys, it's a lot easier to understand and those with keyboard experience will of course have an easier time with this. Keys to its left, bass buttons to the right. Comes in a lot of sizes starting from 20 key, 12 bass all the way up to the full 41 key, 120 bass. The bass comes in either Stradella or free bass system. When a key/button is pressed as the bellows are pushed/pulled in either direction, the same note is played which makes it unisonoric.
- Chromatic Button Accordion – more popular in Europe called the Russian Bayan. Similar to the piano accordion, when you press a button/key, the same note is played even if you push/pull the bellows unlike the diatonic. Both sides consist of buttons which makes it easier for your fingers to reach notes, with its left consisting of bass buttons in either Stradella or free bass system and 3-5 rows of chromatically arranged buttons on the right.
- Diatonic Button Accordion – also known as the melodeon and usually used in folk and Cajun music. Typically consisting of 2-3 rows of buttons in the diatonic scale, it also uses buttons except it is bisonoric, meaning pressing one button and pushing/pulling the bellows will get you 2 different notes instead of the same, similar to the harmonica. Its bass system is also different with a certain number of buttons per treble buttons on its right side. There are some diatonic accordions that are unisonoric though.
- Concertina – is also diatonic and comes in hexagonal/octagonal shapes with straps for your hands instead of your back, making it very lightweight and compact compared to the others. The number of buttons vary per instrument and is usually used in traditional English, Irish and German music. The concertina does not have bass, thus only plays melodies.
Perhaps you're wondering what is the Stradella and free bass system. The stradella bass system is used on most accordions and plays fixed chords on certain rows while the free bass system plays individual notes and is commonly used by classical players.
A lot to take in, but basically just choose whatever instrument will suit you and the sort of music you're looking to play. Search who plays what on YouTube and give it a listen or better yet go to your friendly neighborhood accordion store and try some out. Note that if you're based in the US, most accordions are piano accordions in the stradella and it seems like a lot of resources for learning online are the same. Don't let that hinder you though, you just keep doing you.
Further knowledge