The compound noun "speed-up" is a modern formation from the 20th century, directly derived from the phrasal verb "to speed up." Its logic is transparently literal, combining the core concept of "speed" with the directional particle "up," which commonly denotes increase or enhancement in English (as in "build-up," "break-up"). The word "speed" itself has an intriguing journey from its Old English meaning of "success" or "prosperity" to its current primary association with velocity, a shift that occurred by the late Middle English period, influenced by the concept of "success" being tied to swiftness of action. The particle "up" maintains its ancient Germanic sense of upward movement, here metaphorically extended to signify a rise in rate or intensity. Thus, the term's formation follows a clear and productive pattern in English, where a verb phrase is nominalized to describe the resulting state or action.

Structure: speed (rate of motion) + up (to a higher degree) - speed: From Old English spēd (success, prosperity, power), later evolving to mean "rapidity of motion." Its functional role is the core noun, providing the base concept of rate or swiftness. - up: From Old English up, upp (upward, aloft). Its functional role is an adverbial particle, modifying the core noun to indicate an increase or intensification of the base concept.