Pronunciation: [kastˈɔːɹɪˌə͡ʊ] (IPA)
Correct spelling for the English word "Castorio" is [kastˈɔːɹɪˌə͡ʊ], [kastˈɔːɹɪˌəʊ], [k_a_s_t_ˈɔː_ɹ_ɪ__ˌəʊ] (IPA phonetic alphabet).
Correct spelling for Castorio