The function seems to work well for words that are proper nouns or names of people or places. It does not work as well for more abstract words like "sunshine" or "Bear".
Based on these experiments, it seems that the function is applying some kind of mapping or translation from one word to another. The mapping appears to be based on the meaning or context of the words, rather than their literal spelling or pronunciation.
Now it's your turn to run experiments and see if you can come up with a simple description of the function's behavior!