When Chinese student Du Juan brought her American boyfriend home two years ago to use the toilet, her Japanese roommate became so upset that she shouted in English: "I hate you."

Du, then 21 and an undergraduate at Bridgewater State College in Massachusetts, was shocked. So was her boyfriend.

"I did not think the presence of a male visitor could be cause for hatred," she said.

The Japanese student complained to the campus supervisor, but school authorities sided with Du and said they were also puzzled why the situation warranted hatred.

"Later I realized that she didn't literally mean what she said and that she was not aware of the full meaning of the word 'hate' in English," said Du.

"It was more a problem with translation," she added.

Cultural differences can cause confusion about what words or even actions mean, an issue that has come to the forefront recently following the arrest of a Chinese doctoral degree student in New Jersey.

Zhai Tiantian.[File photo]

Zhai Tiantian, who studied at the Stevens Institute of Technology, has been accused of trying to set fire to a campus building and of making threats to a professor who gave him a low mark.

No physical altercation took place but Zhai reportedly said something along the lines of "at worst, I will risk anything on the line." The professor called the campus police.

According to the indictment sheet, Zhai is facing the serious charge of making a terroristic threat.

For a few days, Chinese media mistranslated, or misunderstood, the charges and reported that Zhai was being charged with terrorism.

The charge of making a terrorist threat can include a range of verbal threats, according to an Associated Press report.

Officials at the Stevens Institute issued a clarification, saying they were concerned the story was being misreported and that a long-running disciplinary situation has been blown out of proportion into an international incident.

The Stevens officials also said that several foreign news reports indicating Zhai was arrested for questioning authorities were incorrect.

Some language experts have speculated that the disagreement between Zhai and the professor can also be chalked up to cultural and linguistic differences.

"What Chinese people regard as acceptable speech may be regarded by Americans as threats," said Luo Gang, the Chinese Consulate's Overseas Chinese Affairs consul. "This is an unfortunate incident. Even though Zhai intended no harm, he has done himself a great deal of harm."

"While I don't know enough about the incident to say what happened, it's certainly true that, in general, people speaking a second language don't always have a complete understanding of the weight of what they're saying," said 30-year-old American Eveline Chao, author of the Chinese slang book Niu Bi and a Princeton graduate in English.

"So it's certainly possible that someone might curse in a second language and not realize how strong the curse is," said Chao.

Most languages also have a hierarchy of words to express anger. Some words are mildly offensive, while others are nearly unspeakable. But for foreign learners, this hierarchy may not be obvious.

"Some words come across a lot harsher in English than when said in Chinese," said Kevin Jones, 23, an American student at the International School of Business and Economics in Beijing.

"There are still words in the US that people generally don't say that might be more acceptable to say in Chinese," said Jones.

But Zhai's case touches on the fine line between the freedom of speech and making threats of terrorism that are real, or at least can be reasonably perceived as real, and has stirred much debate.

"In terms of freedom of speech, I imagine that only if the threat had seemed real would anybody have taken action," said Jones.

"There have been several cases of violence in American universities over the years, so the reaction is not unheard of," he said. "I am sure university staff were being cautious. They had to do what they had to do."

In China, a dispute between a student and a professor over a low mark is rare, but in the US things are different, said Chao.

"There is more of a sense of being on an equal level with your professors (in the US). There are even American professors who allow students to address them by their first names," said Chao. "In China the dynamic between Chinese students and their professors is much more hierarchical."

But she said it's difficult to conceive of any situation where a student would swear at, or threaten, a professor in either the US or China.

She added that she couldn't think of any specific examples of Chinese words that translate into English (or vice versa) with enough difference in meaning to lead to an incident as serious as the Zhai case.

Du, now 23, said she supports Zhai's actions in fighting to save his academic career, but added he needs to learn more about communication in a foreign language.

"Chinese students in a foreign country must prepare more in terms of languages and conversation skills to avoid misunderstandings," she said.