I have a memory of a Spectrum game playing some sort of synthesised speech through the speaker that seemed incredibly ahead of its time. I believe the game was called iBall. And the sample said something like “Fight iBall!” Have I misremembered that? Was this a fever dream?
Although tbf apparently that's done via the AY sound chip of the 128k, which is a lot easier than through the on/off beeper of the 48k since the AY can do digitized audio via CPU-driven volume modulation.
https://www.youtube.com/watch?v=u-D24A_N4d4
https://www.youtube.com/watch?v=hRW9vW3_M3o&t=8
https://youtu.be/yjrbcLm78I8?si=GMIqDdL31hq4ik72&t=87
Although tbf apparently that's done via the AY sound chip of the 128k, which is a lot easier than through the on/off beeper of the 48k since the AY can do digitized audio via CPU-driven volume modulation.
https://spectrumgamesuk.com/index.php?game=Meteor-Storm
I think it said "Meteor Alert!" or something similar, though the quality was terrible.