The universal translator is a staple of science fiction, but Google, Meta and others are locked in a battle to get as many languages as possible working with their AI models.

But researchers warn that the dream of a real-time conversation translator is still some way off.

"We should not imagine that the 200x200 language pairs will be at the same level of quality," said researcher Francois Yvon of Facebook's model.

Meta's innovation, trumpeted in 2020, was to break the link with English -- long a conduit language because of the vast availability of sources.

Instead, Meta's models go direct from, say, Chinese to French without going through English.

In May, Google announced its own great leap forward, adding 24 languages to Google Translate after pioneering techniques to reduce noise in the samples of lesser-used languages.

The challenge of automatic translation is "particularly important" for Facebook because of the hate speech and inappropriate content it needs to filter, Yvon told AFP.

European languages, for example, would probably always have an advantage simply because there are more reliable sources.

The tool would help English-speaking moderators, for example, to identify such content in many other languages.

Meta's promotional videos, however, focus on the liberating aspects of the technology -- amateur chefs having recipes from far and wide appearing at their fingertips.

And the ultimate nut to crack is inventing a tool that can seamlessly translate the spoken word.

"We're not there yet, but we're working on it," said Antoine Bordes, who runs Fair, Meta's AI research lab.

He said Meta's speech translation project works on far fewer languages at the moment.

"But the interest will be in connecting the two projects, so that one day we will be able to speak in 200 languages while retaining intonations, emotions, accents," he said.