Final answer:
The sound de-DUMM is that of a(n) iamb, the most common foot in English.
Step-by-step explanation:
The sound de-DUMM is that of a(n) iamb, the most common foot in English. An iamb is an unstressed syllable followed by a stressed one (/ x). For example, the word 'forgot' is iambic, with the stresses naturally falling on 'for' and 'got' in the sequence.