Among several ways to spell the “long i” sound in English is the 3-letter combination -igh- as in sight [sīt].
The spelling reflects an earlier pronunciation in which the gh represented a sound made with the soft palate, rather like the ch heard in German ich.
The -igh- spelling has persisted in English because it occurs in a small group of high frequency one-syllable words. It’s easy to tolerate an apparently difficult spelling when one sees it frequently.
Most of the -igh- words end with the /t/ sound and spelling. Exceptions are high, nigh, and sigh, in which –igh represents the final sound.
The other most common -igh- words are:
bright from O.E. beorht, byrht
fight from O.E. feohtan
flight from O.E. flyht
knight from OE cniht, cneoht
light from O.E. le￼oht
might from O.E. meahte, mihte
night from O.E. niht
right from O.E. riht
sight from O.E. sihth
The word delight has come to be grouped with the -igh- words because of association with the word light. Etymologically speaking, delight belongs with sprite and spite. All three words come from the French.
delight – from Old French delit, deleit, from delitier, deleitier
sprite – from Old French esprit
spite – shortened from despite which comes from Old French despit
In the 16th century, sprite was often spelled spright and spite was spelled spight. Since then, they’ve reverted to spellngs closer to their origins, probably because they are not in such frequent use as delight.
In case you haven’t come across the word sprite as anything but a brand name, I’ll define it:
A sprite is an other-worldly creature, like an elf or a fairy. The word derives from the same source as “spirit,” but spirit has a more serious connotation than sprite. A sprite plays tricks.