The only instrument I'm able to play is my voice. I can usually pick up a tune by ear and reproduce something that's at least close to the original.
While in grammar school, I signed up for a music class and was given a violin to take home. After a few screeches, I was told to take the violin back and not bring it home again. Bottom line, I didn't learn how to read music or play an instrument. Several years ago I bought an electronic keyboard, a few books and some CDs, and taught myself to read a little music. My objective was to correlate what I saw on a score with what comes out of my mouth (see note).
I play an electronic keyboard about as well as I type on a computer keyboard, and my wife says I'm the fastest 1-finger typist she knows. In addition to the lack of dexterity, I can't read more than a couple of notes at a time, so I'm continually having to read and look for the next note. I now understand why, when I was a kid and knocked on other kids' doors, their parents would say "Johnny can't come out to play, he's practicing playing the piano".
BTW when my Dad was around 8 years old, my grandfather used to take him around the rich people's houses to sing and make some money to help feed the large family. Check out the photo taken c 1919. I learned just a couple of years ago, while talking with my Dad's remaining sister, that it all came to an end when his voice broke.
Note: my objective has not yet been achieved.