What are currently used computational models/frameworks of language acquisition?
Desired features:
models that are biologically plausible (such as neural networks). Personally, I have used cascade correlation neural nets to model pronoun acquisition in children, but in hindsight, I consider this framework to be not neurobiologically plausible.
models/frameworks that can model learning of both L1 and L2 in children and adults, and capture the observed differences.
Related question:
Computational models of early learning in children on CogSci.SE