The word "frightfulnesses" is a mouthful, which is why it's important to break it down using the International Phonetic Alphabet (IPA). The first two syllables contain the vowel sound /aɪ/, represented by the letter "i". The "ght" combination is pronounced as /f/, whereas the "fu" is pronounced as /frʌt/. The final syllable has the sound /əs/, indicated by the letter "e". This all results in the spelling of "frightfulnesses", which means something that induces fear or dread.