Origin and history of respell

early 14c., spellen, "read letter by letter, write or say the letters of;" c. 1400, "form words by means of letters," said in most etymology sources to be from Anglo-French espeller, Old French espelir "to mean, signify; explain, interpret," also "spell out letters, pronounce, recite."

This French word is from Frankish *spellon "to tell" or some other Germanic source, from Proto-Germanic *spellam (source also of Dutch spellen, Old High German spellon "to tell," Old Norse spjalla, Gothic spillon "to talk, tell").

The native cognate word is Old English spellian, spillian "to tell, talk, speak, discourse." Only Barnhart seems to allow that the modern English word is partially from the Old English one, due to the difference in sense.

Klein's sources suggest a possible origin for this Germanic group in a PIE root *spel- (2) "to say aloud, recite, speak with emphasis" and cognates in Greek apeilē "threat" among other words, but Beekes finds the suggestion "rather far-fetched."

Also in early use speldren, from Old French espeldre, a variant of espelir. Related: Spelled; spelling.

In early Middle English still "to speak, preach, talk, tell," hence such expressions as hear spell "hear (something) told or talked about," spell the wind "talk in vain" (both 15c.). The meaning "form words with proper letters" is from 1580s.

Spell out "explain step-by-step" is recorded from 1940, American English. Shakespeare has spell (someone) backwards "reverse the character of, explain in a contrary sense, portray with determined negativity."

word-forming element meaning "back, back from, back to the original place;" also "again, anew, once more," also conveying the notion of "undoing" or "backward," etc. (see sense evolution below), c. 1200, from Old French re- and directly from Latin re- an inseparable prefix meaning "again; back; anew, against."

Watkins (2000) describes this as a "Latin combining form conceivably from Indo-European *wret-, metathetical variant of *wert- "to turn." De Vaan says the "only acceptable etymology" for it is a 2004 explanation which reconstructs a root in PIE *ure "back."

In earliest Latin the prefix became red- before vowels and h-, a form preserved in redact, redeem, redolent, redundant, redintegrate, and, in disguise, render (v.). In some English words from French and Italian re- appears as ra- and the following consonant is often doubled (see rally (v.1)).

The many meanings in the notion of "back" give re- its broad sense-range: "a turning back; opposition; restoration to a former state; "transition to an opposite state." From the extended senses in "again," re- becomes "repetition of an action," and in this sense it is extremely common as a formative element in English, applicable to any verb. OED writes that it is "impossible to attempt a complete record of all the forms resulting from its use," and adds that "The number of these is practically infinite ...."  

Often merely intensive, and in many of the older borrowings from French and Latin the precise sense of re- is forgotten, lost in secondary senses, or weakened beyond recognition, so that it has no apparent semantic content (receive, recommend, recover, reduce, recreate, refer, religion, remain, request, require). Also compare 19c. revamp.

There seem to have been more such words in Middle English than after, e.g. recomfort (v.) "to comfort, console; encourage;" recourse (n.) "a process, way, course." Recover in Middle English also could mean "obtain, win" (happiness, a kingdom, etc.) with no notion of getting something back, also "gain the upper hand, overcome; arrive at;" also consider the legal sense of recovery as "obtain (property) by judgment or legal proceedings." 

And, due to sound changes and accent shifts, re- sometimes entirely loses its identity as a prefix (rebel, relic, remnant, restive, rest (n.2) "remainder," rally (v.1) "bring together"). In a few words it is reduced to r-, as in ransom (a doublet of redemption), rampart, etc.

It was used from Middle English in forming words from Germanic as well as Latin elements (rebuild, refill, reset, rewrite), and was used so even in Old French (regret, regard, reward, etc.).

Prefixed to a word beginning with e, re- is separated by a hyphen, as re-establish, re-estate, re-edify, etc. ; or else the second e has a dieresis over it: as, reëstablish, reëmbark, etc. The hyphen is also sometimes used to bring out emphatically the sense of repetition or iteration : as, sung and re-sung. The dieresis is not used over other vowels than e when re is prefixed : thus, reinforce, reunite, reabolish. [Century Dictionary, 1895]