1. Knee-leeks is basically what onions were called before we adopted (or were made to adopt) a version the French word

2. the old English name for "spear" was "gar"*. "Garlic" is literally just a modern interpretation of "gar-leek".

What about regular leeks? They're just, well, leeks.

* Spear(wielding) Danes are mentioned as "Gardena" in the third word of the commonly seen image of the first page of Beowulf.