Scientists at Lancaster University have observed the hidden tongue movements accompanying a centuries-old change in English speech - offering a rare glimpse of language transforming in real time.
Linguists have used ultrasound imaging to observe one of these changes as it unfolds inside the mouths of speakers from Blackburn, Lancashire - one of the few places in England where many older speakers still pronounce the historical strong-R sound after vowels in words like star and heart.
By imaging the tongue during speech, the researchers uncovered differences between older and younger generations, providing direct evidence of how an ongoing sound change is reflected in the physical movements of speech.
Lead author Dr Danielle Turton, from Lancaster’s School of Social Sciences, said: “English has changed beyond recognition over the past 1,000 years. We can see the evidence of this in Shakespeare, Chaucer and particularly older texts such as Beowulf.
“However, language isn't just something that changed in the past. It is changing all around us, all the time, in such small increments that we rarely notice it happening.
"We can never observe language directly inside the brain, but we can get physically one step closer by observing the movements that create speech. Ultrasound allows us to see tongue movements that would otherwise be completely hidden."
Using the same ultrasound technology commonly used to scan babies in the womb, researchers at Lancaster University have been able to watch how the tongue moves during speech.
The study examined speakers from Blackburn, Lancashire - a community that has retained one of England's last traditionally rhotic accents. The research found that, while older speakers on average produced strong tongue gestures associated with the distinct R sound, younger speakers showed systematically weaker articulations, providing new evidence that this historic pronunciation continues to decline.
Dr Turton added: "We often think about language change through old books or historical recordings. But language is changing all the time, at an incremental pace often too tiny to observe. What's exciting here is that we can actually monitor the physical movements involved in a sound change that's happening today."
The findings also demonstrate the value of ultrasound for understanding language variation and change. Traditional analyses rely largely on what speech sounds like. By observing how sounds are physically produced, researchers can uncover patterns that would otherwise remain invisible.
The work forms part of a growing body of research using articulatory imaging to understand how accents change over time and how speech is produced across different communities.
The study, "Rhoticity in Decline? An Ultrasound Study of Lancashire /r/” was funded by the Leverhulme Trust and is published in Language and Speech. DOI: 10.1177/00238309261478619.
The research was led by Dr Danielle Turton and co-authored by Dr Robert Lennon, both at Lancaster University.