Because "Usagi" of course is literally "rabbit", and we're getting the full mental translation effect. Mom says "Usagi", and the mysterious language handling center in his brain converts it to "Bunny" for the parts of his mind that still operate in English.
Oh, and by the way, yeah! More!
Of either or both!
-- Bob
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For Jor-El so loved the Earth, he sent his only begotten son...
Oh, and by the way, yeah! More!
Of either or both!
-- Bob
---------
For Jor-El so loved the Earth, he sent his only begotten son...