For tones, yes. That's exactly what I meant. But armed just with loudspeaker tech you'd have quite some time trying to develop a reliable system with voice aler

For tones, yes. That's exactly what I meant. But armed just with loudspeaker tech you'd have quite some time trying to develop a reliable system with voice alerts, let alone dozens of them. This became possible in more recent times when playing voice recordings (or synthesize it) for dozens of types of alerts became technologically feasible and reliable enough to use in critical scenarios.