They exchanged names, which indicated that the language here was the same as the one used in the Primeval Chaos Universe.
Since the spoken language was the same, the written language was essentially the same as well.
In truth, even if the language and writing had been entirely different from the Primeval Chaos Universe, such a barrier would be nothing at all to someone like Lin Fei today. Learning a language and script would be a matter of a single thought.
Chapter 1660