WHEN Kazuhiro Fuchi talks about Japan's program to build computers able to understand human language, he appears assured. The director of the Institute for New Generation Computer Technology (ICOT) does not worry that computers might some day become too independent for human control, as depicted in such science fiction movies as ''2001'' or ''Brainstorm.''
''I don't think it will happen in 100 or 200 years. . . . We know such dangers could exist from reading science fiction, so we are trying not to go that way. The more technology advances, the more human beings think. That's why I think it will work out,'' assures Dr. Fuchi.
A more immediate concern for Fuchi is that Japan might lose a global race to design the next - or fifth - generation of computers.
His institute, launched three years ago with about 40 of Japan's top thinkers , was designed to push Japan into the forefront of advanced computer technology. It was also meant to help dispel a long-held image that the Japanese are better at imitating technology than inventing it.
Three years ago, when Fuchi first started, many people were skeptical of the project's viability. No longer. In the United States a group of scientists, such as Stanford professor Edward Feigenbaum, have been pushing ahead with research into ''artificial intelligence'' and the Pentagon has put in $600 million to join the race.
The fifth-generation project has fired up the Europeans as well. Britain has launched a five-year ''Alvey'' program, while another European science group is working on a ''Esprit'' program.
Japan's project is sponsored by the Ministry of International Trade and Industry, academics, the government-run Nippon Telegraph and Telephone Corporation, and Japan's eight leading electronic manufacturers. This $450 million, three-phase plan is expected to stretch over 10 years.
Fuchi refutes persistent rumors that the government is slashing the budget for this project. In the coming year he expects about 5.1 billion yen ($20.7 million), which he considers ''moderate'' given the Japanese government deficit, he says.
So far ICOT has been on target as it nears the end of its initial phase of three years ending March 1985. During this period it has developed a technology base for the future computers that will help it to ''think'' along human lines.
These machines would still process information one step at a time, as in present computers.
So in the intermediate phase the Japanese institute will develop prototype hardware and software for machines that can conduct several processes at the same time, or in ''parallel.''
The final stage will be the development of a prototype machine that will process a complex network of information and which will understand normal language.
Public interest is fixed on the future computer's artificial intelligence - the ability of the machine to make logical inference.
While the present generation of computers can give answers to some questions, it can't tell you how it came up with that answer. But an inference machine will tell you, making such a computer more ''similar'' to the human thought process.
Exactly how clever the the computer will be is difficult to define, but Fuchi likens it broadly to the intelligence level of a primary or even a slower secondary-school child.
He cautions, however, that such an analogy could be misleading because even young children have a remarkable understanding and learning ability that's still much more advanced than that of any computer, ''at least for the forseeable future.''
Fuchi hopes to use the knowledge of a university professor whose information bank is most systematically organized.
But Fuchi has his own dream - that the new computer will make society more democratic.
''We have a democratic form of government, but only politicians or bureaucrats have information. And other people can't submit good proposals because of the lack of information or the lack of ability to deal with information transaction,'' explains Fuchi. ''Therefore the ordinary people have to obey what officials decide.''
The hierarchy of a company boardroom could be done away with, too, he says, and workers would be able to participate much more in the corporate decisionmaking process. But the realist in him admits that ''things don't always go so simply'' and that the computer could fall into the hands of the ''privileged'' who might try to use it to manipulate other people.
Scientists around the world are more keenly interested than ever in his work, says Fuchi, noting a huge turnout at the recent symposium in Tokyo on fifth generation computers. At the meeting, he faced criticism from some American scientists who thought that the Japanese were taking too narrow and inflexible an approach by adopting ''Prolog'' (Programming in Logic).
This approach, invented by the Europeans, can serve as a basis for fifth-generation computer language. Europeans argue that the Americans were irritated that Japan adopted a European system instead of an American one. But Fuchi believes that it is the best system, adding that he is willing to change once he's proved wrong.
''Such criticisms have been decreasing now that everyone is beginning to realize that we are not eliminating other possibilities. I think that more people are beginning to have the same view,'' Fuchi says confidently.
Many European scientists attending the conference generally appeared convinced that Japan will succeed in its computer drive. But the general view was that Japan's strength lay not so much in its ability to innovate but in its knack for organization and application.
One French computer specialist said that he wasn't impressed so much by the novelty of the hardware that ICOT has produced as by the Japanese determination to go ahead with their plan.
Alain Colmerauer, who fathered the concept of ''Prolog,'' said that the Japanese don't do much research themselves, but they are good at synthesizing fundamental research.
''They have an astonishingly open mind and don't care about the different schools of scientists,'' he added.
Before ICOT adopted his concept, Fuchi was not taken seriously in Japan, Mr. Colmerauer told a reporter. Fuchi himself admits that ''in the past Japan lagged behind the US,'' and that there are still fewer researchers in Japan compared with the US.
''Therefore I am trying to train young researchers,'' he says, which is the hidden purpose of this project. He also insists, however, that Japan has its own strong points.
''I would say that we have better organization and a better philosophy'' than the US.
''There are a lot of creative ideas in America, but they don't seem to know what to do with them because of their lack of organization,'' Fuchi says.