Pronunciation: [ɡɹˈɛtə͡ʊ] (IPA)
Correct spelling for the English word "Gretto" is [ɡɹˈɛtə͡ʊ], [ɡɹˈɛtəʊ], [ɡ_ɹ_ˈɛ_t_əʊ] (IPA phonetic alphabet).