SpellSynth

SpellSynth started from the speaking spelling toys of the late '70s: type a word, hear it speak. The 1978 toy fit its whole built-in vocabulary in 32 KB of ROM, because the chip never stored sound, only a small recipe for every 25 ms of a word, and rebuilt the voice from it each time it spoke.

SpellSynth's English word folder is 28 MB. Mine stores each word as ordinary audio, then works out a similar recipe itself when it loads the word and plays it through the same kind of filter. A phone has room for the audio. The toy didn't.

All three of my retro voices run the word through a 10-pole filter. The big difference is what goes in: a chirp for 1978, plain 100 Hz clicks for 1986, slower, lower clicks for 1968.

The display is a 14-segment font, and the letter V took four shapes, three of them in one day. A neat symmetric V on that grid is just a Y, so I ended up copying the lopsided V from a hobby font. It speaks French now too, built after the 1981 French edition of the toy, with 360+ French words.