“Do you think they hear us? We’ll make them hear us!”. This was the rallying call Greta Thunberg gave to 250,000 people in New York’s packed streets, and millions worldwide who were taking part in the largest climate protest in history. In political chambers and on the streets, her cutting and inspiring words have awakened countless people to the climate and ecological emergencies. But beyond them, her voice contains a message that’s just as powerful.

The sound of Thunberg’s voice has become as distinctive as her bluntly precise rhetoric and diminutive figure, as evidenced by her recent uncredited opening monologue on indie rock band The 1975’s album, A Brief Inquiry Into Online Relationships.

There’s a certain poetic justice here. After first learning of the environmental crisis facing the planet, Thunberg was diagnosed with Asperger’s syndrome, depression, and selective mutism, and describes herself as “only talking when necessary”. The very presence of her voice in the public sphere alone therefore signals the urgency of the climate and ecological crises.

And in making her voice heard, its unique characteristics tell their own important story.

The sonic fingerprint

The human voice is like a fingerprint made of sound waves. Unique to each speaker, its composition is determined by an array of factors ranging from the size, age and sex of the speaker’s body to their emotional state and social background.

As a result, when a person vocalises, the voice connects the individual to the collective. When we speak, we carry and communicate our own personal identity to the community we enter. When we listen, we’re listening not only to the meaning of the words spoken but also the non-linguistic information communicated by the speaker’s sonic fingerprint.

The most salient characteristic of Thunberg’s vocal fingerprint is perhaps her age. Just as Malala Yousafzai’s youthful tones gave her drive for female education such sway, Thunberg’s voice is a clear reminder of her 16 years – and by extension, the adolescence of the thousands of school strikers she has galvanised. She frequently frames the climate crisis as a generational conflict between the adults who are exacerbating the problem and the children who will pay the price. It is the youth in her voice, over and above her chastising words, that makes this role reversal so powerful.

The political landscape surrounding the climate and ecological crises is constantly changing. So is the human voice. How she alters her approach to public speaking as her voice shifts into adulthood could be important if she is to keep having an impact – she will only sound like a student for so long.

A voice through a crowd

The wide reach of Thunberg’s public speeches also turn an issue too often expressed with faceless statistics and global trends into a human one.

On paper, it would be easy to write off Greta’s words as another opinion among many. But as well as physical characteristics, our voices communicate our emotions. Thunberg’s terse and sombre monotone makes tangible the emotional significance of the deepening crisis facing her generation.

In embodying the issue of climate breakdown, Thunberg’s voice also makes it personal. When she speaks, we are reminded that she is one individual – and that her actions alone inspired hundreds of thousands to join her. As the title of her recent collection of speeches says, No One Is Too Small to Make a Difference.

Thunberg and her followers argue for systems change, but they do so as a chorus of individual voices. The quarter-million strong unified chant of Thunberg’s name at New York’s climate strikes reminds us that when individuals are empowered and brought together, they can each play an important part in tackling climate and ecological breakdown.

The voice is not just a vehicle for language. The unique sounds of every human voice tell their own story alongside the words they carry. For Thunberg, this is the story of a generation let down and determined to effect change – whether leaders like it or not.

As the movement she started continues to gain momentum, this message will underpin everything she and her followers say. Whether people are listening is another story.

DAMIEN POLLARD is a PhD Candidate, University of Cambridge Centre for Film & Screen at the University of Cambridge.

THIS ARTICLE WAS ORIGINALLY PUBLISHED ON THE CONVERSATION