The Shuffle can play a playlist of audio, which could include the French Language Learning you plan on listening to, but the Shuffle can't remember your playback position within a file. If you listen to the whole playlist in one sitting, or don't want to use Smart Playlists, or can remember where you left off, the Shuffle will do fine.
Smart playlists and remembering playback position is something the iPod Nano can do that the Shuffle can't.
So if you plan on listening to your learning, and each learning file is say 45 minutes long, and you pause at 30 minutes in, and put the shuffle away for the weekend, on Monday your position within the 45 minute learning session will be lost. It may even forget where in the playlist you were.
If you use a Nano, you can use smart playlists and the Remember playback position feature and never lose your place.
The Shuffle is smaller and has the built in clip to keep it with you easily.
The Nano holds 8 times more data, has no clip, double the battery life, a screen to see the playlists and tracks, and EarPods instead of ear buds, plus the smart playlist capability. But it costs 3x more.
The Playlists are:
Standard playlist: X_Learning_Disc_1 contains all the tracks for a single CD of content (or more if you wish) where each track is marked as Remember Playback Position and Skip on Shuffle in iTunes.
Smart playlist: Learning Disc 1, rules: Playlist is X_Learning_Disc_1 and Plays = 0.
As you finish tracks they fall out of the Learning Disc 1 playlist. When you pause they mark the position in the song file information in the iPod Nano. If you sync while paused, the position is copied to iTunes. Play in iTunes and you start from the same location. Pause in iTunes, sync again and the position is copied to the Nano. Listening to the playlist will pick up exactly where you left off.