It's only an assumption. The original poster didn't specify if he meant the babytalk, so we don't know if he means that.
Even if he did, I've met so many people (couples, in specific)with different natioalities, including English speakers, who make up 'pet names' for their significant other pronouncing them in a 'babytalk' sort of way, so that has nothing to do with 'pretty heavy engrish'.
'Engrish' originally refers to the bad use of English grammar (more often spoken), but as far as I remember, I haven't found any of the dialogues that sounded 'Engrish' to me. That's why I was curious why the original poster said that :0
EDIT to add a very embarrassing example: One of the ways you can refer to your significant other in Spanish is 'Amor'. I used to call an ex 'Amurr". It sounds stupid and one could argue 'Amurr isn't used in Spanish!' but the thing is, it was our thing. Just like, I dare to assume, 'biby' and wormy' are exclusive to the intimacy of the characters. So yeah, that's it guys, pardon the loooong explanation, I'm a translator who studied linguistics, and these things are my jam.