The world's biggest consumer electronics firm said Wednesday it had developed a machine that can hear a sentence in Japanese and, moments later, speak it in English.

Matsushita Electric's prototype system, co-developed with Carnegie Mellon University of Pittsburgh, is the world's first to understand speech that it hasn't already been pre-programmed to recognize.But it could be four years before monolingual Japanese can venture abroad without fear, voice-translating machine in hand, the company says.

The system, a bulky desktop computer with other pieces of equipment added, is capable of comprehending only simple descriptions of medical symptoms and has a vocabulary of only about 50 words, enough to recognize some 3,000 expressions.

Matsushita is developing software for other situations such as checking into a hotel and clearing customs. It is also researching English-to-Japanese interpretation, a far more difficult task due to the complexity of spoken English sounds.