Pronunciation: [d͡ʒˈiːsɛl] (IPA)
Correct spelling for the English word "Giesell" is [d͡ʒˈiːsɛl], [dʒˈiːsɛl], [dʒ_ˈiː_s_ɛ_l] (IPA phonetic alphabet).
Correct spelling for Giesell