YOU SAID:
my cat said he wants a yellow duck
INTO JAPANESE
私の猫は彼が黄色いアヒルを望んでいると言った
BACK INTO ENGLISH
My cat said he wanted a yellow duck
INTO JAPANESE
私の猫は彼が黄色いアヒルが欲しいと言った
BACK INTO ENGLISH
My cat said he wanted a yellow duck
That didn't even make that much sense in English.