yes this is in ottoman turkish.
top two lines: "bütün dünya işçileri birleşse rahmet dünyaya hakim olacaktır" translation: "if all the workers of the world unite, mercy will rule the world"
right middle is the number 12.
left middle is abbreviation ş.h. but i don't know what that stands for. the communist party at that time was sosyalist fırka so it would be s.f so i can't take another guess.
edit: fixed the last word.