The spelling of the word "OPDDE" can be explained using IPA phonetic transcription. The first three letters, "OPD," are pronounced as /ɒp dɪ/ in British English, with the "O" sound pronounced as the short "o" sound like in "hot," and the "P" and "D" sounds pronounced as in "pod" and "did." The last two letters, "DE," are pronounced as /dɛ/ with the short "e" sound like in "bet." Therefore, "OPDDE" is pronounced as /ɒp dɪ dɛ/ in British English.