The first time I took part in an operation I had no idea what was going on. As a new medical student I hadn't learned the language of surgery. I didn't even know there was a language of surgery. A few years later, as a surgeon myself, this language had become second nature and I didn't even know I was using it.

Of course there are many voices in the operating theatre. They don't always say what they mean or mean what they say. And sometimes the most important voices are those that don't use words at all.

For several years I've been leading research projects that investigate how people communicate during surgery. At Medicine Unboxed in Cheltenham, I'm going to explore how to read some of these surgical voices and make sense of what they say.

Of course the story starts with the patient. What happens to their voice during surgery? At first glance, it seems to have disappeared altogether, especially if the operation needs a general anaesthetic. In the anaesthetic room the patient gradually relinquishes autonomy, leaving behind their personhood and their power to speak for themselves as powerful drugs make them unconscious.

But they haven't stopped communicating. Speech mutates into a language of the unconscious body. Functions that we take for granted and scarcely notice – our heart beating, our lungs breathing, our blood circulating – are represented by wavy lines on a screen or the beep of a machine. Words have turned into traces, and the voice of the anaesthetised patient has become transformed.

Throughout the operation the surgical team monitors this wordless commentary, this constant unconscious broadcast of the body. Any variation – a change in rhythm, a subtle inflection of pitch – will put the team on high alert. The team has become fluent in the language of unconsciousness.

When the operation is over, when the wound is closed and the dressings are in place, the anaesthetist disconnects these machines and hands back the power of speech.

Reading voices

In the operating theatre, different voices are in play. At the centre is the scrub team – those who operate on the body itself. Around them are other members of the group – equally important but differently so – and all have different voices.

The surgeon's voice is often muted, soft, muffled by a mask. Intended for the scrub team only, it may be inaudible beyond. Voices spread out in ripples from the scrub team: requests for instruments, instructions to others in the theatre. The anaesthetist, the operating department practitioner, the runner nurse – all have their ways of speaking, their vocabularies, their own vocal fingerprint.

The voices you hear depend on where you're standing. Like conversation at a party, there are ebbs and flows, natural rhythms and patterns. Often you can't make out the words, but you have to interpret the many meanings within this soundscape of surgery and recognise when they involve you. You develop new sensitivities, new ways of reading what is said.

What do these voices convey? Some are the voices of people talking in ordinary words. But others are different. Some are distorted voices, pulled out of shape by their peculiar setting. Some are transformed voices, expressed through machines instead of words. And some are silent voices, conveying their message by what they do not say.

Reading voices isn't easy. For a newcomer, the operating theatre is an overwhelming place. Sound is all around: beeps, alarms, the noise of people moving. Sometimes music. And speech, when it surfaces, uses an alien language, peppered with abbreviations and jargon.

Once you get used to it, you can tell how things are going the instant you step in. If all is well, there's a general buzz of conversation, movement, activity. But if things are going badly, you sense the tension without even knowing how. The most eloquent voice of all is the voice of silence: the voice that says 'we've got a problem here and we all need to focus on fixing it'.

In my conversation at Medicine Unboxed, I hope to unpick some of these ideas, exploring what's different about surgical voices and what they can and cannot say.

Roger Kneebone is professor of surgical education at Imperial College London and a Wellcome Trust Engagement Fellow

Medicine Unboxed is a project that connects the public with healthcare professionals in a scientific, political and ethical conversation about medicine, illuminated through the arts. For more information on this year's event in Cheltenham, 23-24 November, visit our Facebook page, follow @medicineunboxed, or visit our Pinterest boards to learn about the conference programme