re-

The prefix 're-' is, along with 'un-' and 'in-,' one of the three most productive prefixes in Modern English.‌​‍​‍​‍​‍​‍​‌​‌​‌​‍​‌​‌​‌​‍​‌​‌​‌​‌​‌​‍​‌​‌​‍​‍​‌​‌​‌​‌​‌​‌​‍​‌ It descends from Latin 're-' (again, back), which entered English through Anglo-Norman French in the Middle Ages and has become so thoroughly naturalised that it attaches freely to verbs of any origin.

The Latin prefix 're-' is itself of uncertain ancestry. De Vaan describes the root as 'of obscure origin,' and while older comparative dictionaries tied it to a Proto-Indo-European root *wret- or *wre- meaning 'to turn, bend back,' modern scholarship treats the etymology as disputed. What is clear is that 're-' was already a fully productive prefix in Old Latin (where it often appeared as 'red-' before vowels), and it retained this role throughout the Latin period.

In Latin, 're-' expressed two closely related senses: (1) repetition or doing again, as in 'redo' would translate; and (2) reversal or backward motion, as in 'recede' (to go back), 'retreat' (to draw back), 'retract' (to draw back). The two senses continued into English essentially intact, and modern 're-' words usually fall into one or the other category: repetition ('rewrite,' 'redo,' 'restart,' 'replay') or reversal ('recall,' 'retreat,' 'repel,' 'revoke').

The Old Latin form 'red-' survives in English before vowels: 'redact,' 'redeem,' 'redemption,' 'redolent,' 'redound,' 'redundant.' This 'd' is the oldest feature of the prefix, a Proto-Italic relic preserved when the following vowel would otherwise produce hiatus. Most other words drop the 'd,' giving plain 're-.'

The prefix entered English in quantity during the twelfth through fifteenth centuries, borrowed as part of Anglo-Norman and Latin learned vocabulary: 'receive,' 'recover,' 'reduce,' 'refer,' 'refuse,' 'regard,' 'reject,' 'release,' 'remain,' 'remember,' 'remove,' 'repair,' 'repeat,' 'reply,' 'report,' 'require,' 'rescue,' 'reserve,' 'resist,' 'respect,' 'respond,' 'rest,' 'return,' 'reveal.' In most of these the prefix was not analysable by English speakers — 'report' is not parsed as 're-' + 'port' — because both the prefix and the base entered together as a unit.

In Early Modern English (c. 1500–1700) 're-' became fully productive as a prefix speakers could add to any verb. It began attaching freely to native Germanic verbs: 'rebuild,' 'remake,' 'rewrite,' 'reread,' 'redo,' 'reseek,' 'reset.' This is a hallmark of a prefix that has broken free of its borrowed origin.

In spelling, 're-' is often hyphenated when it attaches to a word beginning with 'e' to avoid misreading ('re-enter,' 're-evaluate,' 're-examine') and when the meaning differs from an existing un-hyphenated form. 'Recover' (regain) differs from 're-cover' (cover again); 'resign' (quit) differs from 're-sign' (sign again); 'release' (free) differs from 're-lease' (rent again). These hyphenated doublets are a useful reminder that the prefix is semantically live and can produce new meanings at will.

Some 're-' words have drifted far from their Latin base. 'Remember' comes from 're-' + 'memor' (mindful), originally 'to bring to mind again.' 'Regret' comes through Old French from 're-' + a Frankish root for 'weep.' 'Repent' comes from Latin 're-' + 'paenitere' (to cause to regret). 'Repair' comes from 're-' + 'parare' (to prepare), originally 'to restore.'

Phonologically, 're-' has two main pronunciations in English: the unstressed /rɪ/ or /rə/ in fully naturalised words ('review,' 'return,' 'receive') and the stressed /riː/ in analysable coinages ('re-do,' 're-write,' 're-read'). The stressed form signals a transparent, live prefix; the unstressed form signals a fossilised, historically borrowed unit. Many 're-' words have both pronunciations depending on context: 'remake' can be pronounced /ˈriːmeɪk/ (the noun, as in 'a remake of the film') or /riːˈmeɪk/ (the verb).

Representative 're-' words include: rebuild, recall, receive, recognise, recommend, record, recover, reduce, refer, reflect, refuse, regard, reject, relate, release, remain, remember, remove, rename, repair, repeat, replace, reply, report, require, reserve, resist, respect, respond, restore, result, return, reveal, reverse, review, revise, revive. Reversal examples: recede, recoil, refund, regress, reject, relapse, repel, repulse, retract, retreat, revoke, revolt.

In contemporary English 're-' is perhaps the single most productive prefix for forming new verbs. Any verb can take 're-' to mean 'do again,' and speakers readily coin nonce forms: 'rescroll,' 'retweet,' 'refollow,' 'reboot,' 'respawn,' 'rematch,' 'resubmit,' 'rerun.' Software and technology vocabularies are particularly rich in 're-' coinages because repetition and restoration are such common operations.