Moreover, complex hierarchical temporal expressions, such as the Tuesday before last or the third Wednesday of each month, and ambiguous expressions, such as last Friday, are difficult to handle using deterministic rules and would benefit from a recursive and probabilistic phrase structure representation.
we attempt to learn a temporal interpretation system where temporal phrases are parsed by a grammar, but this grammar and its semantic interpretation rules are latent, with only the input phrase and its grounded interpretation given to the learning system.