Pronunciation: [ˈɛffˈa͡ɪfəsən] (IPA)
Correct spelling for the English word "FFIFESN" is [ˈɛffˈa͡ɪfəsən], [ˈɛffˈaɪfəsən], [ˈɛ_f_f_ˈaɪ_f_ə_s_ə_n] (IPA phonetic alphabet).
Correct spelling for FFIFESN