OK, finally this morning, here is a worksheet on the Latin word root liter. While it sounds like it should be related to a measure of liquid (as we use it by itself in English), it actually means letter. Now you know why you find it at the root of words like literature in English. Needless to say, this is a very productive root in English.
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.