Talking alarm clock knew one sentence: "Three, two, one, go!". Which I've borrowed from Grand Prix Simulator, old 8-bit Atari game.
Speech sythesis module was constructed from simple TTL integrated circuits and worked like this: Clock signal from oscillator was fed into chain of four 4-bit counters. These counters generated an address, which addressed the EPROM containing the sampled speech. In each byte, eight 1-bit samples were packed. They were sequentially extracted from the byte using 1-of-8 multiplexer and then fed to the speaker.