"Dumpest" is the superlative form of the adjective "dumb". In IPA phonetic transcription, it is written as /ˈdʌm.pəst/. The first syllable "dum" is pronounced with the vowel sound /ʌ/, as in "sun". The second syllable "-pest" is pronounced with the consonant sound /p/ followed by the vowel sound /ə/ as in "about". The spelling of "dumpest" follows the English spelling rule of adding -est to the end of a short adjective to indicate the highest degree of that quality.