The members of the Erythronium genus go by a number of peculiar common names, seemingly used interchangeably among the species. Fawn-lily, Trout-lily, Adder’s Tongue, and Dogtooth Violet.
Now everyone knows that it got the name Trout-lily because the leaves look like a brook trout. From that, you can presume that Fawn-lily also came from the spotted leaves.
A little research suggests that the bulb looks like a dog’s tooth, hence Dogtooth Violet, even though it’s not a violet and only sort of looks like a violet. Now I need to go dig some up and take a look.
If you look closely, the central spike, which is the pistil, is sort of split in two, thus looking somewhat like a snake’s tongue. At least that’s what it says on the internet, which is an infallible source of information. Seems like a stretch to me.
All in all, I find it interesting to speculate why ancient mankind came up with the various peculiar names for plants.