The word "soapest" has an irregular spelling that may cause confusion. It is pronounced /ˈsoʊ.pɪst/ and is derived from the word "soap". The suffix "-est" is added to indicate the superlative form. The spelling of "soapest" is unique because the letter "a" is used to represent the sound of the letter "o" in the root word "soap". Other words with a similar spelling include "loaves" and "breaths", which also have irregular plurals. It is important to pay attention to the spelling of these words to avoid common spelling errors.