The booth is soundproofed. That is the first thing they tell you. Whatever happens inside the glass stays inside the glass.

Mariam had worked the ICC's Arabic channel for six years. She knew the protocols: 30 minutes on, 30 off. Speak in the first person at all times. Maintain professional detachment.

Before her first assignment she had signed a declaration before a judge of the court: I solemnly declare that I will perform my duties faithfully, impartially, and with full respect for the duty of confidentiality. Her colleague Lena had told her, afterward, that the trick was to think of yourself as a vessel. The words pass through. They are not yours.

At 14:07, the defendant's counsel began his direct examination.

Mariam did not recognise the man at first. She was looking at the screen, not the dock. The dock was peripheral. She had been trained not to fix on the accused's face because it slowed the lag and broke her concentration.

What she heard first was the Arabic, West Sudanese dialect, the specific flattening of certain consonants that belonged to Wadi Salih and nowhere else on earth. She had not heard that dialect in 22 years.

She kept going.

I will perform my duties faithfully.

The accused was explaining to counsel that he was a man of limited authority. A local coordinator. Someone had borrowed his name, his nickname, for reasons he could not account for.

He had not been present at the locations specified in the indictment. The burden of proof, he reminded the court, rested with the prosecution.

Mariam translated: "I was not present at the locations specified. The court should note..."

She looked up.

His profile. The shape of the ear. A slight forward tilt when he listened, like a man accustomed to noise.

She had seen that tilt in a courtyard at the edge of a village in West Darfur in the summer of 2003, and she was seeing it again in a climate-controlled courtroom in The Hague, and there was no air between those two facts. They were the same fact, and had been from the start, waiting.

Lena touched her arm. A signal: too long a gap. Mariam heard her own voice resume as if from a distance.

"...that all decisions of a senior character were made in Khartoum. I received orders and did not issue them."

First person: the ICC standard. The interpreter does not summarise; she becomes the speaker for the duration of the utterance, speaking as though the words are hers, because the record requires it, the law requires it, and the right to a fair trial requires it. Mariam's headset carried his words into her body and out through her mouth as I.

His denials are her I. Every account of the summer of 2003 is her I. The description of his whereabouts that August, a market town and a cousin's house, nowhere near Galania, arrives in English as her I, spoken into the court record for the judges, the transcript, and history.

In her village they had called him something else. Not his name. A title, a role.

She had been nine years old and she had seen him in the courtyard of the house where her uncle lived, speaking to men who were not from Wadi Salih, and her mother had pulled her away from the window before she could hear what was said. Her mother had been good at that. Pulling her away before she could hear.

A European university accepted her 14 years later. She had a gift for languages: Arabic, French, Fur, and the English she had learned from a radio her father kept wrapped in cloth. The ICC posted the role at the end of her second year. She had applied without telling her mother.

Counsel asked whether the defendant had ever given orders for the targeting of civilian populations. The accused shook his head. He said it quietly.

"No. I did not. An old man, with grandchildren. That is what I am."

Mariam's voice in the headset, level, almost bored, the professional register she had spent years building, word by word, like a structure that would not fall.

Galania had 1,200 people in August 2003. She knew this from the indictment, which she had studied before the trial as part of her preparation, as all interpreters studied the relevant documentation. The indictment described what happened there in numbered paragraphs. It used the passive construction, as legal language does: civilians were attacked, structures were burned, persons were forcibly transferred.

The passive hides the actor. Finding him was the trial's purpose. He was in the dock, speaking in his West Darfuri dialect, insisting on his absence, and Mariam was speaking for him.

Lena touched her arm again. She realised she had paused. Not long. A second, maybe two.

She resumed.

"I was not involved in any military operations. The court must understand: the man they are describing is not me. There is a confusion."

There is a confusion.

She said it perfectly. Neutral, clear, in the first person, at the right lag. Nothing in the transcript would show it. The judges would not know.

Nothing in the record would flag it. This is what soundproofed means.

At 14:37, her 30 minutes were done. Lena took over. Mariam removed her headset and sat back in her chair.

Outside the glass, counsel was asking a new question. Inside the booth, Lena's voice was quiet and steady and exact.

Mariam looked at her hands.

She had been nine years old. What happened in the courtyard, she had not seen. Her mother had been good at that. Pulling her away.

Teaching her, without saying so, that survival sometimes requires not-knowing. Not-knowing as a skill. A discipline.

That foundation had taken 22 years to build.

The man from the courtyard sat in the dock, and in six minutes she would put the headset back on and become his voice again, because that was the work, because the work was what justice needed to function, because someone had to speak the words precisely and impartially even when the words were his, even when the first person was his I and not hers, because the record mattered and the transcript mattered and the law mattered and she had signed a declaration before a judge and she was going to keep it.

She straightened in her chair.

Five minutes.