Most seals have carved into them the name of the artist and are used along with a signature or in place of one. But seals can also include favorite phrases, poems, religious texts, pictures, or any combination of these. Just like a stamp made anywhere in the world, you can have a seal carved in any language. Even the ancient Chinese sometimes used Mongolian or other languages on their seals. in fact, you can include anything you want on a seal. For me, what distinguishes a Chinese seal is not the language used but rather the technique and materials which give them their distinctive look.