COMPARISON OF ADVERBS AND ADJECTIVES: 2

The RELATIVE SUPERLATIVE of adjectives is expressed by preceding the comparative form with the definite article:
"il più giovane" <the youngest>;
"la meno veloce" <the least rapid>;
"i meno intelligenti" <the least intelligent>;
"le più attive" <the most active>.
(The definite article is not repeated if it already precedes the noun:
"la ragazza più intelligente" <the smartest girl>.)
The ABSOLUTE SUPERLATIVE of an adjective (indicating degree rather than comparison) is regularly formed by adding the suffix "-issimo," which is then inflected like a regular adjective:
"un libro utilissimo" <a very useful book>;
"una donna bellissima" <a very beautiful woman>.
The ABSOLUTE SUPERLATIVE of adverbs is formed by adding "-issimamente" to the stem of adverbs ending in "-mente" but "-issimo" to the stems of other adverbs:
-issimamente -- "lentamente" <slowly>, "lentissimamente" <very slowly>;
-issimo -- "spesso" <often>, "spessissimo" <very often>.
Adjectives and adverbs are sometimes doubled to express an absolute superlative:
"parla piano piano" <speak very softly>