Having no other eventful thing to write about, I give you this little paper I wrote for a Linguistics course in 2008.
The prefix re-, in English, attaches to transitive verbs and alters their meaning so that the definition becomes whatever action the verb describes, repeated. When the re- prefix is attached to a verb base, the base is augmented by the phonetic sequence /ri/. For re- words complying with the rule of re- as defined above, the resulting term may be decomposed and the original verb extracted; there are no additional syllables or sounds needed to construct a re- word except re- and a verb, such as build. When the base verb, build, is combined with the prefix re-, the word becomes rebuild. The definition of the word rebuild is “to build something again.” When one removes the prefix re- the base is still build, which is the same verb that was contributed to the composition of the re- verb: rebuild.
However, many words do not comply with the re- prefix rule as defined above. For example to reduce something does not mean to “duce” it again – in fact reduce, in its modern usage, is not even a verb denoting a repetition of action. When something is reduced, say the size of an onion by peeling it, nothing is being done to it again, it’s not being made smaller again – except perhaps in a manner recalling its origins: as the seed of an onion, which makes the verb a verb of repetition. The Latin word “ducere” meaning: to bring or lead, when augmented by the prefix re- (meaning, as stated above: “back, or again”), becomes “reducere,” a word which originally meant “to bring or lead back again;” the word acquired a connotative sense of restoration and eventually the meaning “to bring [restore] to a simpler or lower state.” In time reduce, from being a synonym for restore, came to mean “diminish in size.” In this case, to reduce the size of an onion, or anything, is to make it smaller again, like it was before – in the original sense of the word – to restore it to a previous state. Everything (theoretically speaking) was once smaller than it is now. If indeed we all started out as two subatomic particles colliding in the vacuum of space and time before the big-bang, any reduction in size is a restoration and thus a repetition of a particular state of being. While there are English words beginning with the prefix re- that do not comply with the prefix-base rule, all words beginning with the prefix re- do share the original definition of a repeated action. As we all know, words come from many places, some of them traveling ridiculous and convoluted routes in order to find their place in current and common usage, but nevertheless, words that bear the prefix re- have in common the insinuation of a repetition and an origin that denotes a repetition (even the word repetition).
While discussing scientific theory may solve the problem of the use of a seemingly nonsensical base in the word reduce, not all abnormal re- verbs can be so simply explained. Even more obscured by common usage are re- words that are not verbs, but adjectives or nouns such as the word revenue, a synonym for income, which has been used since its appearance in Late Middle English as a noun, derived from the past participle of the French verb “revenir” meaning literally, (from the Latin, “re-, back; venire, come”) “returned.” Revenue is an English noun meaning “income,” or the money that a company or person makes (yearly, monthly, or by whatever period). However, no one company or person actually creates money (except the government); in the business world a certain amount of money or time is invested in a company or its market and the investor or employee then, hopefully, sees their investment return to them at the end of a period. Therefore, however obscured by common usage a re- word becomes, the Latin prefix retains its meaning.
Also worthy of note is the alteration of the phonetic sequence of the re- prefix when its base is not an English transitive verb. In the case of revenue, the first syllable retains the French pronunciation, /r / rather than the high front vowel sound /ri/, of prefix-base verbs like rebuild. Words such as relax and repeat can share an accented first syllable (depending on context and personal idiolect) with the traditional re- verbs, but other re- constructions like remember and repetition have inconsistently placed stresses. In the word remember the pronunciation of the prefix is an unaccented /r∂/, the accent moving to the second syllable (/m m/). Common speech tends to see the reduction of unaccented re- prefixes, which occur in non prefix-base re- words, to lower back vowel sounds such as /∂/, / /, and /u/.
The vast majority of words beginning with the letters /r/ and /e/ retain the Latinate (French) meaning of a repeated action or state. A single noted exception is the word /rend/, a “poetic” term meaning “to tear,” which is Germanic in origin and has no relation to any of the rules discussed above.
Sources: Oxford English Dictionary, American Heritage Dictionary.