A Crown prosecutor in the Air India trial spent another day frustrated by a defence witness who today admitted that he has been answering questions in English he can't understand.

Richard Cairns read back the testimony of Kamal Jit, a New York cab driver, whom the defence has called on to raise doubts about an important Crown witness.

Jit admitted to Cairns that he has not understood most of the questions he had been asked in English, nor the answers he himself had given in English.

"When you are asked a question, your practice is to give an answer when you don't understand?" asked Cairns. "It's not my habit, but little bit I understand, then I answer," Jit said.

Cairns asked him if he understood the questions at the time they were asked.

"I don't remember," Jit said.

"If I understand the question I would have said 'Yes.' I don't remember now," Jit said.

On Wednesday, proceedings were temporarily halted when Cairns asked Jit, during cross-examination, if he was an idiot.

Jit is among the final defence witnesses. He testified Monday that the important Crown witness, an FBI informant known as "John," had sought money from the family of accused bomber Ajaib Singh Bagri so he could flee to India to avoid testifying.

Bagri and Ripudaman Singh Malik are charged with eight counts, including conspiracy and murder, in connection with the two bombings on June 23, 1985.

The first blast killed two baggage handlers transferring a Vancouver suitcase to an Air India flight at Tokyo's Narita Airport.

Later, Air India Flight 182, en route from Toronto to India, exploded off the coast of Ireland, killing all 329 aboard.