cuman , slavic or balcanic?

Hi together

I should have a question :
I am interested to know how, after all rules of transformations of
the word it should be normal to transform the word "romanus" in
slavic - or turkish languages.

I point out the diferences among :

latin=romanus
romanian=roma:n
slavic=ruma:n
turksh= ruma:n

I see the difference in the "rom" and "rum" and I ask myself if this
is from lingvistic point of view of relevance of not.

Best regards,

a. moeller