The live subtitle text at the bottom of the screen on the BBC News channel and possibly other TV news providers, that scrolls horizontally, is created by a speech recognition system and may contain transcription*, spelling and grammatical errors, sometimes unintentionally humorous or embarrassing. Brevity is more important than grammatical correctness. The text is intended for viewers with hearing difficulties or where a TV screen is displayed with the sound turned off, e.g. in public waiting areas in hospitals, airports, rail stations, etc.
...as the likes of newsreaders and presenters talk on TV, one of the
designated 200 English-speaking subtitlers from across the globe will
sit in front of a microphone repeating whatever’s said on air.
Doing this means a clear voice, free of any background noise, can be
processed by specialised audio recognition software that generates
captions on the screen. It’s a hybrid system – one that relies on a
computer and subtitler.
So, if Matt Baker says “Hello and welcome to The One Show” amongst a
backdrop of applause, there’ll be a single subtitler somewhere clearly
repeating “Hello and welcome to The One Show” into a microphone. And,
without the noise of the clapping, the computer can produce the
caption “Hello and welcome to The One Show” on screen.
How do TV Subtitles work? (BBC)
*BBC rugby bosses have had to correct an unfortunate subtitling error
after the words 'Nigel Owens is a gay' was brandished across TV
screens during their high-profile England versus Scotland coverage at
WalesOnline readers picked up on the gaffe which appeared after 65
minutes when the world's number one referee yellow carded England
flanker Sam Underhill at Murrayfield.
The subtitle explanation of the decision, captured in the screen-shot,
read: 'Yellow card. Nigel Owens is a gay penalty and yellow card.'
The Beeb quickly corrected it to read: ' Nigel Owens is saying penalty
and yellow card'.
A BBC Spokesperson said: “Our live subtitling service produces
accuracy levels in excess of 98% but, as with all broadcasters, there
are instances - particularly during live broadcasts - when mistakes
"On this occasion the voice recognition subtitling software made an
error which was spotted and corrected immediately."