More than a taste
In present-day English, sweet is first of all the taste of sugar, honey, ripe fruit, and anything that mimics them. It also names a wider kind of pleasantness: a fragrant room, a tuneful line of music, a kind face, a person who is gracious rather than sharp. As a noun it can mean confectionery, a dessert course (especially in British usage), or someone dear. The casual interjection that marks approval is a late, informal offshoot of the same adjective, not a separate word.
That spread is not a modern fashion. English has used one form for both sugar-taste and general agreeableness since the Old English period. Many related languages do the same: a word for this taste is also a word for what simply feels good.
Inherited on the island
The origin of the word sweet is native Germanic inheritance, not a borrowing from French or Latin. Old English already had swēte in the West Saxon written standard and swoete in Mercian, together with a shorter related form swōt. Middle English kept several spellings at once: swete, sweete, swoote, and soote. The last of those, familiar from Chaucer’s April rain that is soote, continues Old English swōt rather than swēte. Both belong to the same adjective; they are not rival etymologies.
Standard dictionaries record the word in English before the year 900. The Oxford English Dictionary treats the adjective as inherited from Germanic. The noun is later conversion inside English: by about 1300 it could mean something pleasant on the tongue and, at the same time, a beloved person; by about 1400 it could mean a sweet food or drink. A candy drop as a specific sense is much later, around 1851, after sweetie had already been used of a confection in the early eighteenth century. Old English did have a noun swete, but it meant sweetness as a quality, not a piece of candy.
Across the North Sea the family is easy to recognize. Dutch zoet, German süß, West Frisian swiet, Swedish söt, Danish sød, Norwegian søt, and Icelandic sætur all continue the same Proto-Germanic adjective. Comparative handbooks reconstruct that ancestor as swōtuz (from an earlier swātuz). Some older discussions write a ja-stem swotja- instead. The disagreement is about how the Germanic stem is modeled, not about whether English sweet is a native word.
An older adjective, not a prefix puzzle
There is no hidden prefix in sweet. It is a simple inherited adjective whose comparative and superlative (sweeter, sweetest) are ordinary English morphology. The interesting structure sits further back.
Behind the Germanic form lies a Proto-Indo-European adjective given in modern notation as swéh₂dus, from a root sweh₂d- meaning sweet or pleasant. Older dictionaries print the same root as swād-. The two spellings are a change in scholarly convention, not two competing stories. English did not import the word from Greek or Latin. Those languages kept their own descendants of the same remote adjective.
Latin suāvis meant pleasant or delightful and was not, in the first place, a taste term. Through French it yields English suave, a genuine doublet: same deep ancestor, a later arrival with a courtly social meaning. The Latin verb suādēre, to advise or persuade, is built on the idea of making something agreeable. That is why persuasion and the older word suasion sit in the same historical neighborhood, even though they entered English by a Romance route rather than the Germanic one.
Greek hēdýs meant sweet or pleasant; the related noun hēdonē, pleasure, is the source of hedonism. Sanskrit svādú covers delicious and palatable as well as sweet. Tocharian A swār and Tocharian B swāre are also cited in the comparative literature with the sense sweet. The pattern is consistent: the taste and the feeling of pleasure travel together.
Senses that grew without replacing the core
Several specialized uses grew beside the everyday ones. Late Old English already applied the adjective to water that is fresh rather than salt. By the mid-thirteenth century it could mean wholesome rather than spoiled; milk that is still sweet is milk that has not turned. Visual beauty and desirability are recorded from the mid-fourteenth century. Chemistry in the 1660s used the word of substances free of corrosive salts and acids. The oil industry later called crude or gas sweet when it is free of sulfur compounds, a use dated to 1919. The opposite there is sour crude, not a dessert.
To be sweet on someone, meaning infatuated, is attested by the 1690s. Jazz musicians in the 1920s used sweet of music played at a steady tempo with little improvisation, set against hot. None of these is folk etymology. They are ordinary extensions of pleasant, unspoiled, or not harsh.
British English kept the noun close to the table: sweets for confectionery, a sweet for the pudding or dessert course. American English prefers candy and dessert for those jobs, while the adjective itself remains fully shared on both sides of the Atlantic.
The useful pair
The most concrete takeaway is the pair sweet and suave. One word never left the Germanic line and kept the everyday taste. The other came through Latin and French and settled on polished manners. Both go back to the same Indo-European adjective for what is pleasant. When English needed a word for sugar on the tongue, it already had one of its own.