The compound adjective "sweet-talking" is a relatively modern formation, drawing on the deep Germanic roots of its components. "Sweet," from Proto-Germanic swōtuz, carries the ancient sense of pleasantness, which was metaphorically extended to describe agreeable speech. "Talk," related to "tale," originates from the Proto-Germanic talō, meaning narrative or account. The combination, employing the adjectival '-ing' suffix, literally means "speaking sweetly." This construction follows a transparent English pattern where an adjective modifies a verbal noun to describe a manner of action, evolving from a literal description into a term for persuasive, often insincere, flattery.

Structure: sweet (pleasing) + talk (speak) + ing (adjective/participle suffix) - sweet: From Old English swēte, meaning pleasing to the senses, agreeable. In this compound, it functions as an intensifier describing the nature of the speech. - talk: From Middle English talken (to speak), of Germanic origin. It functions as the core verb, indicating the action of speaking. - ing: A suffix from Old English -ende, -inge, used to form present participles and adjectives from verbs. Here, it creates an adjective describing someone who engages in the action.