Does two-weapon fighting stack with flurry?

[Particle_Man]

Unearthed arcana gives an alternate barbarian ability called whirling frenzy that gives them an extra attack. It might well "stack" with extra attack(s) from two-weapon fighting (although a barb. would likely be better off with a 2-h weapon anyhow).

Hmmm...this is tricky. I don't know about the monk flurry with lagatang (exotic weapon) and "flurry" from the exotic weapon master class. Hmm...