Token German chiming in
You got most of it quite right, except the ending. It’s -erle, or really just -le (depending on where you split the word). The suffix is used to change a word to sound smaller, cute, playful and generally less serious. It also has a southern accent/sound to me, but take that with a pinch of salt. Not sure if there is an english comparison. Its similar to another german suffix: -chen
The most successful aquatic reptile of our time