OK, so back before ice age, I recall having a Sinclair ZX80 PC (with TV as a display, and a cassette tape player as storage device).
Obviously, the programs on cassette tapes made a very distinct sound (er... noise) when playing the tape... I was wondering if someone still had those tapes?
The reason (and the reason this Q is programming related) is that IIRC different languages made somewhat different pitched noises, but I would like to run the tape and listen myself to confirm if that was really the case...
I know these come up on auction sites like Ebay quite frequently - if you want to buy them yourself. If you get someone else who owns one to listen then you are going to get their subjective opinion :)
In any case, the language used to save it would be the secondary cause of the pitch changes - it will be related to the data. IOW you could probably create a straight binary data file that sounded very similar to a BASIC program (the BASIC would have been saved as text, as it is interpreted).