Correct spelling for the English word "Sopper" is [sˈɒpə], [sˈɒpə], [s_ˈɒ_p_ə] (IPA phonetic alphabet).
One who dips something in liquor that is to be eaten.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.