My basic approach to lip sync is fairly old-fashioned. I take my dialog into JLipSync and work out the timing. In addition to saving out an x-sheet from JLipSync, I write out an actual paper x-sheet so I can easily refer to it later. (As a side note, you could also use Papagayo for this step. Papagayo is slicker and more polished than JLipSync, but I find JLipSync to be more flexible.)
Then I just use that x-sheet to animate the dialog by hand. I usually don’t use the list importer method because I want to be able to make specific shapes (and sometimes specific breakdown shapes) that fit the dialog and acting. (Not that I’m particularly good at this last part yet, but it’s the goal that counts. )
One other thing: I’m still new to animation in general and I’m still developing both my drawing/animating skills and, on top of that, a decent work flow with open source software. So far, though, I’m finding that for character animation in particular, I wind up using a mix of Synfig and Pencil - Synfig if the motion is simple or cyclical, Pencil if it’s more eccentric. That in turn means that some of the dialog gets animated in Pencil and, as such, it’s not auto-tweened. So, to make dialog consistent across a project, I usually use constant interpolation for dialog in Synfig and animate any passing positions manually, so as to give it a slightly more traditional animation feel. That may all change as I get better at the process, but that’s how I do it for now.
To check the timing on dialog for a finished sequence, I set up a file in the Blender VSE with my image sequence from Synfig (or Pencil, as the case may be) and the dialog sound clip. The cool thing about this set up is that Blender just references the assets, so if I update the image sequence by outputting a new sequence from Synfig, that update is automatically reflected in Blender.
For what it’s worth, a while back I wrote about my work flow over at the Pencil forum:
lesstooges.free.fr/pencil/forum/ … php?id=792
That’s still mostly accurate, though I’m slowly increasing what I can do with character animation directly in Synfig. I’ve also finally started learning to use Blender for animation (as opposed to just using it to edit video) and I’m looking forward to discovering how it may fold back into a 2D project.