About the 1951 Czech Finian's Rainbow

I don't read Czech, but with Google translation I managed to recognize from the back cover that "Nahrano 23, unora 1951" means "recorded on Feb. 23rd, 1951". At the beginning and between songs, there're well-recorded conversations or narration of the show, which don't sound like from a live performance. Hope some Czech friend can explain exactly what kind of recording this is.

By the way, the cast list of this recording looks the same as the 1948 studio cast recording. But this one says recorded in 1951, so I added it as a new recording.