Can music written for guitar be played on an Autoharp?

Yes. You would simply play the chords shown for the guitar on the autoharp. Where a C is indicated, push the C button, etc. Strum a rhythmic pattern similar to the guitar. Remember, chords are chords wherever you find them. For instance, a G chord on a guitar is a G on a piano, or a banjo, or an accordion, or anything else that can play chords. Any music that shows the chord names can be used for autoharp.

Autoharps are limited by the number of chord bars they have. A large harp has 21 chords. Some have more, most have less. Sometimes you have to play a simpler form of a chord on the autoharp than is shown for the guitar. For instance, the chord Cadd6 would be just a plain C on the harp. Sometimes you have to change the key because the needed chords are not on the autoharp. A piece written in C# would not be available on the autoharp so you would play it in C major.

Agreeing with Tim - in some of the classes I taught for years, we used autoharps. Again - music played is limited by chords available. And I had a friend whose frail elderly Dad was close to death - but still wanted to play his guitar. He found he did not have the strength. So I had my friend get his Dad an Autoharp - Dave would push the buttons, Dad would strum. Just enough to make him feel he so could still play *something*. And I also used autoharps with my Special Needs classes - one girl said is sounds good, but mostly it FEELS good when it sound pretty.

It would depend on the music but if it was something written specifically for guitar then it would require a lot of ingenuity and skill, and I doubt a lot of it could be played exactly as written.

An autoharp is mainly used as a chordal instrument and even then the chords available are limited. I know there are players who go beyond this and seem as if the could play anything but they are exceptions and I still think much of the guitar repertoire would not be possible even for them.

Sort of, since the autoharp is a chordal instrument.

Yeah, notes and chords apply to any pitched instrument.