Question

"I wrote it all by myself." What part of speech is "by" in this context?

Answer 1

I don't really understand the question... You could mean "by myself" if you want to know who it was by, or you could mean "I wrote it all" if you want to know what you did "by myself"..

Answer 2

I think it's a preposition in this context?

Answer 3

Prepositions are generally these short phrases or words which link together other words, indicate location, etc. ..."by" appears to play that role in this case.