I really wish I could figure out what this was! I tried to match it to multiple Internet streams, no luck. They were either incorrect, unreliable, or not extant at all. Darn it! Anybody have a clue? Here's my log.
730, UNID, 0838-0901. English to Spanish translations of the closing ceremony of the Olympics in London. Into Spanish talk in a female voice just at the hour, then definitely heard Big Ben's chimes. SIO originally 333, fair in some static and subject to interference from both sides, but signal degraded to 322 with time.
From previous posts here, looks like you're in WI. This could easily be XEX from Mexico City listed at 100kw. I hear them frequently from my location. As Poet mentioned, KSVN also broadcasts in Spanish, but that indeed would be a rare catch from these parts.