The contemporary ubiquity of absolutely as the expression of a high degree of affirmative emphasis (instead of yes, oh yes, very much, etc.) is often accompanied by a hypermetrical stress on the initial syllable, which means that the stress of this anapestic adverb becomes spondaic, i. e., with a ternary foot bearing two stressed syllables instead of one. Incidentally, this case of spondee resembles the more general expression of emphasis in French, where the obligatory stress on the ultima is augmented by a second stress on the initial syllable, as in fOrmidAble or mErveillEUx (capitals signifying stressedness).
The occurrence of the spondee in the anapestic word absolutely is to be explained as yet another discursive implementation in English of the poetic function (focus on the message for its own sake), structurally of a piece with alliteration, with which it shares the feature of repetition of identical elements, here manifested in its most basic form, that of DOUBLING, and as a prosodic rather than a segmental feature. In turn, the possibility of spondee helps explain the otherwise unmotivated rise to monopoly status of absolutely as the preferred form of emphatic affirmation in contemporary English.