I always misspell the word <relevant> as <*relavant> based on a thinking that <relevant> is related to <relative>. I recently decided to look up <relevant> to do a word study in the hopes of teaching myself the correct spelling. If SWI could help me remember the spelling of <tomorrow> by learning that <To + Morrow -> tomorrow>, then SWI could also help me remember the spelling of <relevant>.
I started my study by looking <relevant> up on Etymonline. The word comes from Middle French <relevant> meaning “depending upon; helpful,” which came from Medieval Latin <relevantem> (nominative <relevans>), from the stem of the Latin <relevare> “to lessen, lighten.” The entry also told me to see the entry for <relieve>. I learned that <relieve> comes from the prefix <re> meaning “gain, back, anew, against” and the Latin <levare> meaning “to lift up, lighten.”
I then looked up <levare> in a Latin dictionary. Bases derive from the 2nd and 4th principal parts of a Latin verb. The 2nd and 4th parts of <levare> are <levare> and <levatus>. The <-are> and <-atus> are the endings, which leaves <lev>, which become the English bases <leve>. The replaceable <e> is needed for the English spelling.
Returning to the Etymonline entry for <relieve>, I see that the word ultimately comes from the PIE (Proto-Indo-European) <*legwh-> meaning “not heavy, having little weight.” Words built from the same <leve> base as <relevant> include <alleviate>, <elevate>, <elevator>, <levee>, and <lever>.
I had to investigate the etymology of <relevant> in order to understand the spelling. When I thought about sounds alone, I falsely linked <relevant> and <relative>. I pronounce <relevant> as [ɹɛləvənt] and <relative> as [ɹɛlətɪv]. The vowel in the second syllable is [ə], so I falsely assumed the grapheme <a> spelled the vowel in both words. But the primary function of English spelling is to represent meaning, not sound. Sounds are still important, but meaning is primary. The word <relevant> is spelled with an <e> in the second syllable because of the base <leve>.
<Leve>
”lighten, lessen, relieve” from Latin levare
Word Sums
Leve + er -> lever
Leve + er + s -> levers
Leve + ee -> levee
Leve + ee + s -> levees
Leve + y -> levy
Leve + y + es -> levies
Leve + i + ty -> levity
Leve + i + ty + es -> levities
Leve + ate + or -> levator
Leve + ant -> Levant
Leve + it + ate -> levitate
Leve + it + ate + s -> levitates
Leve + it + ate + ed -> levitated
Leve + it + ate + ing -> levitating
Leve + it + ate + or -> levitator
Leve + it + ate + or + s -> levitators
Leve + it + ate + ion -> levitation
Leve + it + ate + ion + s -> levitations
Leve + it + ate + ion + al -> levitational
al + Leve + i + ate -> alleviate
al + Leve + i + ate + s -> alleviates
al + Leve + i + ate + ed -> alleviated
al + Leve + i + ate + ing -> alleviating
al + Leve + i + ate + or -> alleviator
al + Leve + i + ate + or + s -> alleviators
al + Leve + i + ate + ion -> alleviation
al + Leve + i + ate + ion + s -> alleviations
un + al + Leve + i + ate + ed -> unalleviated
e + Leve + ate -> elevate
e + Leve + ate + s -> elevates
e + Leve + ate + ed -> elevated
e + Leve + ate + ed + s -> elevateds
e + Leve + ate + ing -> elevating
e + Leve + ate + or -> elevator
e + Leve + ate + or + s -> elevators
e + Leve + ate + ion -> elevation
e + Leve + ate + ion + s -> elevations
re + e + Leve + ate -> reelevate
re + e + Leve + ate + s -> reelevates
re + e + Leve + ate + ed -> reelevated
re + e + Leve + ate + ing -> reelevating
Super + e + Leve + ate -> superelevate
Super + e + Leve + ate + s -> superelevates
Super + e + Leve + ate + ed -> superelevated
Super + e + Leve + ate + ing -> superelevating
Super + e + Leve + ate + ion -> superelevation
Super + e + Leve + ate + ion + s -> superelevations
re + Leve -> releve
re + Leve + s -> releves
re + Leve + ance -> relevance
re + Leve + ance + s -> relevances
re + Leve + ance + y -> relevancy
re + Leve + ance + y + es -> relevancies
re + Leve + ant -> relevant
re + Leve + ant + ly -> relevantly
non + re + Leve + ant -> nonrelevant
ir + re + Leve + ance -> irrelevance
ir + re + Leve + ance + s -> irrelevances
ir + re + Leve + ance + y -> irrelevancy
ir + re + Leve + ance + y + es -> irrelevancies
ir + re + Leve + ant -> irrelevant
ir + re + Leve + ant + ly -> irrelevantly
Relatives
relieve
relief
leaven
legerdemain
carnival
champlevé, from French <champlevé>, from <champ> “field” + <levé> “levee”
