Adjectives and adverbs in the superlative degree are similar to the comparative degree, but use the -est ending and the word “most” instead. In addition, the article “the” must be placed before the adjective or adverb in the sentence. Comparative sentences using the superlative degree are saying that something is the most when compared to the rest of the group.
Consider the following sentences:
Justin is the fastest runner on the track team.
Mr. Copeland spoke the most highly of Juan than the other interview candidates.
Generally speaking, the superlative degree is used when something is being compared to three or more things.
A common mistake with double superlatives is using both the ending -est and the word “most” in the same sentence. Errors with double superlatives can also be identified when the sentence by reading the sentence out loud. For example, the prior sentence would be incorrect if it was written as follows:
“Justin is the most fastest runner on the track team.”
It would be best to remove “most” and keep fastest in the superlative degree.