BBC Micro — Acorn Speech System

An optional voice inside the BBC Micro

The BBC Micro’s Acorn Speech System was an optional internal upgrade, not a voice chip supplied in every machine. Fitting instructions identify the TMS5220 speech processor at IC99 and the phrase-ROM position at IC98. Once installed, the computer had dedicated speech hardware on its motherboard.

The newsreader in the ROM

Acorn’s user guide describes Word PHROM A as containing 165 words and word-parts based on recordings of BBC newsreader Kenneth Kendall. Prefixes and endings could be combined with words to build more useful utterances. The familiar British accent was part of the system’s character.

A processor and its vocabulary

The TMS5220 reconstructs a changing vocal-tract model from encoded speech parameters. Its companion PHROM stores the data needed for the supplied vocabulary. This is more sophisticated than a simple sample player, but the standard word collection is still finite: the processor does not independently convert arbitrary English text into speech.

Beyond the standard word list

The official guide also documents supplying speech data from RAM through the processor’s Speak External command. That capability separates the limits of the supplied vocabulary ROM from the capabilities of the speech processor itself. New speech requires appropriately encoded data and software to feed it.

Another way to build a talking computer

The BBC Micro represents a middle ground between an external speech box and a computer with speech as standard equipment. Acorn designed for internal expansion, allowing an owner to add the voice later. It belongs beside the EXL 100 and Atari 1400XL & 1450XLD as a distinct approach to integrating a speech chip with a home computer.

Specifications

Manufacturer

Acorn Computers

Period

1983

Speech installation

Optional internal upgrade

Speech hardware

TMS5220