I
O, o BrE AmE əʊ AmE oʊ
▷ O's, o's, Os əʊz AmE oʊz —Communications code name: Oscar
▶ ˈ O ˌ level BrE AmE
▶ ˌ O ˈ V ˌ language BrE AmE
II
O, O' in family names BrE AmE əʊ AmE \ oʊ —This prefix is unstressed; it is occasionally reduced to ə
I
O, o BrE AmE əʊ AmE oʊ
▷ O's, o's, Os əʊz AmE oʊz —Communications code name: Oscar
▶ ˈ O ˌ level BrE AmE
▶ ˌ O ˈ V ˌ language BrE AmE
II
O, O' in family names BrE AmE əʊ AmE \ oʊ —This prefix is unstressed; it is occasionally reduced to ə
Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012