There's a fun way to test translation systems. Have it translate something to another language, and then translate it back (after starting a new chat/clearing its memory) and compare. It's best done with some sampling of text that has style, metaphor, parable, etc. After all I think we should be more adversarial than promotional when testing such things. Here [1] is the first paragraph of a human translation of Hantsel and Gretel:
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"Hard by a great forest dwelt a poor wood-cutter with his wife and his two children. The boy was called Hansel and the girl Gretel. He had little to bite and to break, and once when great dearth fell on the land, he could no longer procure even daily bread. Now when he thought over this by night in his bed, and tossed about in his anxiety, he groaned and said to his wife: 'What is to become of us? How are we to feed our poor children, when we no longer have anything even for ourselves?' 'I'll tell you what, husband,' answered the woman, 'early tomorrow morning we will take the children out into the forest to where it is the thickest; there we will light a fire for them, and give each of them one more piece of bread, and then we will go to our work and leave them alone. They will not find the way home again, and we shall be rid of them.' 'No, wife,' said the man, 'I will not do that; how can I bear to leave my children alone in the forest?--the wild animals would soon come and tear them to pieces.' 'O, you fool!' said she, 'then we must all four die of hunger, you may as well plane the planks for our coffins,' and she left him no peace until he consented. 'But I feel very sorry for the poor children, all the same,' said the man."
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And here is GPT 3.5's final rendition of it, after converting it to Japanese and back:
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"Near a large forest, a poor woodcutter lived with his wife and two children. The boy was named Hansel, and the girl was Gretel. They had little to eat, and during a severe famine in the country, they could no longer even provide daily meals. One night, as he lay in bed pondering this, the woodcutter, filled with anxiety, said to his wife, "What will become of us? How will we feed our poor children when we no longer have anything for ourselves?" His wife replied, "Husband, tomorrow morning, let's take the children into the forest. There, we will light a fire and give each of them one more piece of bread. Then, we will go to work and leave the children on their own. They won't be able to find their way back, and we will be freed from them." The man said, "No, wife, I cannot do that. How can I leave my own children alone in the forest? Wild animals will come and tear them apart." She retorted, "You fool! In that case, we will all four perish of hunger, and you can just as well plane the boards for our coffins," and she didn't leave him in peace until he agreed. "But the poor children are so pitiful," the man said."
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It's a generally terrible translation with a simple (though heavily stylized) text. Not only is absolutely all style, imagery, and character eliminated from the writing, but it's also overtly nonsensical in parts. Lighting a fire for the children ends up translated as simply lighting a fire, as if the goal is to start a forest fire. Similarly the man's sorrow for the children ends up being completely lost, and is translated as him simply calling his children pitiful. I'd be curious to see GPT4's output on this, or ideally even more challenging paragraphs.
[1] - http://www.literaturepage.com/read/grimms-fairy-tales-72.htm...