Of particular note are some reinforcements from Old Norse (circa 850s onward):

- are (displacing bēoþ, sind, and sindon)

- their (displacing heora)

- they (displacing hīe)

As a linguistic game, sounds fun. Hopefully its pupils don't take it too seriously, hem hem, e.g. William Strunk the Lesser: "Saxon is a livelier tongue than Latin, so use Anglo-Saxon words"