I've been spending some time recently teaching myself the basics of Old French via
this resource. Like you do. It's a pretty good resource--it takes you through a bunch of contemporary works (Chanson de Roland, Yvain, etc) and teaches you the grammar as it pertains to the text.
Last night, too, I dug up our copy of the Song of Roland*. I was pleased to see that probably half the book is dedicated to the Old French version, so I could read them side-by-side. Also I think I prefer the English translation to the one on the UT instructional site above.
Why the sudden interest in Old French? It isn't just my interest in languages in general. In creating Lucernic, the language spoken in The Lioness Embarked, my in-progress cavalierpunk novel, I wanted a language inspired by both Latin and modern French. Old French, being transitional between the two, fits that description nicely.
Some things I have learned!
1) Old French is not that hard to learn if you know modern French and have studied some minimal amount of Latin. I've have several excited moments of "holycarp, I'm reading old French!" Part of that is because there's a replicable pattern to how graphemes in old French became modern French, i.e. anything with an é in modern French was probably originally es.
2) Old French has declensions. Sorta. The Latin nominative is basically the Old French nominative, but every other Latin case has been dropped into the Old French oblique case. There are two main declensions, which roughly correspond to the Latin first and second declensions, but there are a lot of weird exceptions, too.
Plus we pre-date normalized orthography here, so it's hard to tell the difference between a declension and a spelling variation, sometimes. The UT instructor points out that in reading Old French, we're watching the breakdown of the entire case system, so I sense the declensions are more guidelines than rules.
3) You learn a lot about etymology from this process. For example, the same word, eschec, is used in the Song of Roland for loot, bounty, etc (what the knights get from raiding Spain), and for chess (the modern French word for which is échecs). So literally chess is a game of bounties. Which makes perfect sense as a descriptor of the game, where you sacrifice pieces to gain others. You also realize the origin of words like check, checkmate, exchequer. (Although I've also heard chess, and its associated vocabulary, come down to us from the Persians, so this etymology I've created could be completely fictional).
Now, as for how this affects Lioness... this post got long, so you'll have to wait until
next time for that.
* Even though neither of us has read either--yet!--we own both Song and Orlando Furioso, the Italian retelling of the story. This is largely because Matt is obsessed with the old Bungee game Marathon, which makes many references to the story. And now you know why all his characters in RPGs have names like Durandal, Joyeuse, Pinabel, Berengier, etc.