The spelling of the word "OTOS" can be ascribed to the use of the International Phonetic Alphabet (IPA). The phonetic transcription of "OTOS" is /ˈɔtoʊz/. This represents the pronunciation of the word "Otis," with a z sound being used to represent the plural form. Using the IPA helps to ensure that the spelling of words reflects their true pronunciation, which can be especially useful for individuals learning English as a second language. So, if you see "OTOS" written down, you'll know that it is pronounced like "Otis" but with the sound of a z added to the end.