Correct spelling for the English word "unamplest" is [ʌnˈampləst], [ʌnˈampləst], [ʌ_n_ˈa_m_p_l_ə_s_t] (IPA phonetic alphabet).
There is no such word as "unamplest" in the English language. It seems to be a combination of the prefix "un-" (meaning not) and the superlative suffix "-est" (meaning most), potentially applied to the word "ample". However, "ample" already serves as a superlative form, meaning spacious or abundant. Therefore, "unamplest" appears to be a nonstandard or incorrectly formed word.