I was astonished (don't ask me why!) to discover that the frogs in Greece (or rather, these specific frogs in Greece) really do say 'brekekekex coax coax", completely recognizable from the transcription by Aristophanes. I got a recording of (unseen) adults at this site, posted at www.inaturalist.org/observations/174806198. Meanwhile, scads of tadpoles were clustered in the sheltered shallows of this estuarine marsh, but they turned out to be a different species.