Vic has got a lot O’ Gottle

Under the tutelage of Karl Dr Doolittle’ Dallas, the Chatterbox turns out to be no dummy.


Chatterbox – targeted at the nappy-user or the computer user? Let it speak for itself.

Experimentation is the name of the game with the Chatterbox speech module. Within minutes of power-up I was getting intelligible sounds – although some of them sounded like the ventriloquist’s ‘gottle o’ geer’.

Its powerful features are done no favours by the Chatterbox name and the ‘court jester’ logo, however. It looks as though it is targeted at the nappy user rather than the computer user, and you get the impression that plugging it into an unsuspecting Vic-20 will be the cue for snatches of panto dialogue.

But let its potential speak for itself.

The Chatterbox is about the size of a cigarette case and plugs into the expansion socket of the Vic. It will also plug into the motherboard if you already have a RAM pack fitted.

There are two dongling plugs – actually, a 5-DIN plug and 5-DIN socket – for which no explanation is given in the brief
but clear documentation supplied. You just connect the Vic’s audio/video-out socket to the monitor A/V-in, and sounds come out of the monitor speaker.

If you’re using a demodulator for normal TV display, you plug the Chatterbox into the socket, and plug the demodulator’s 5-pin into the Chatterbox socket.


PCN surgery reveals the electronic vocal chords of Curragh’s Chatterbox.

In use

Speech is synthesised by typing ‘allophones’. These are alphabetical symbols which stand for 62 unique sounds, including five pauses from ten to 200 milliseconds long. The allophones are separated by oblique strokes, so my name becomes:-


P5 and P2 are pauses of 200 and 30 milliseconds respectively, the latter representing the small explosion that follows the initial letter ‘D’ in a word.

For some reason the allophone /C/gave a happier initial sound to my first name than /K/, though both can be used. The /AR/ sound (why not /AH/, since it contains no ‘r’?) seemed to need a brief ‘uh’ before the final ‘I’ – represented in orthodox phonetics by an upside-down ‘a’, and here by the allophone /U/.

The whole name is stored in a string, and voiced by calling SYS 41000. To voice strings longer than the capacity of a single VIC program line, you can concatenate them into sentences. But you must remember to insert pauses between the words.

Any mistake will terminate the computer’s interest in saying your word at the point where the mistake occurred, as will failure to terminate each word with an oblique.

I never managed to get a satisfactory ‘w’ sound, but ‘/OO/EE/’ sounded more like ‘we’ than the more obvious ‘/W/EE’.

The voice itself is completely toneless, and despite the north-eastern origins of its (presumed) inventor, has a slightly mid-Atlantic flavour.

Pressing ‘F1’ causes each letter to be voiced as it is typed in, as well as screen-edit commands such as RETURN or CURSOR. (For some reason this acts only in the unshifted mode, so that CsrDn is voiced, but not CsrUp.) The constant vocal commentary can become distracting if one is typing in a program, but it can be turned off by pressing ‘F3’.

The documentation consists of a 20-page cassette-sized booklet, which begins with a three-page introduction to the theory of allophones. This can be skipped. Tables of the actual allophones and example words are also included. The words are printed with the allophones separated by dashes rather than obliques, and this could lead users astray.

I found a few minor errors and confusions. The suggestion that ‘/DD/ sounds good in initial position and /D/ sounds good in final position, as in ‘daughter’ and ‘collide’ is confusing, since ‘daughter’ has no final /D/. It should have read ‘respectively’.

The allophone table suggests that /DH/ is the ‘mu’ sound in ‘muM’ and /DHH/ the ‘mer’ sound in ‘merM’. but they’re the short and long versions of a voiced ‘th’. This turned out not to be a printing error. The maker differs with me on what /DH/ actually sounds like.

There are two programs, one demonstrating each allophone in turn while printing demonstration words on the screen, the other a speaking clock, which uses the VIC’s internal jiffy-counter to say things such as:-


When I keyed in the demo program. I kept getting a syntax error on a perfectly normal data line. I couldn’t find the cause, but I think I spotted an error in line 565 of the clock program (‘PA5’ where, presumably, they mean ‘P5’).

The manual also says that the allophone /S/ can be doubled to /SS/, but it produced an error when I did this, and I had to use /S/S/.


It’s a pity the manufacturer doesn’t supply a suite of demo programs on cassette, since it is irritating to have to key in a long and at first meaningless (and therefore error-prone) program before you can explore the module’s full potential.

I can imagine wanting to use this neat little add-on (I had it talking within a six-line program in a few minutes) in interactive programs, and I’m quite jealous that I can’t plug it into my business PET. But it should be possible to dissect how it works and write a routine machine code. This would be hard on its inventors, but is, I suspect, inevitable.

  • Machine: Chatterbox Speech Module for the Vic-20
  • Price: £57.45 inc. postage and VAT
  • Available: from branches of Spectrum shops
  • Manufacturer: Curragh Computer Components

First published in Personal Computer News magazine, 25th March, 1983


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