Pronunciation: [ˌʌndəlɪnˈiːʃən] (IPA)
Correct spelling for the English word "underlineation" is [ˌʌndəlɪnˈiːʃən], [ˌʌndəlɪnˈiːʃən], [ˌʌ_n_d_ə_l_ɪ_n_ˈiː_ʃ_ə_n] (IPA phonetic alphabet).
Correct spelling for underlineation