We model utterance production as probabilistic cost-sensitive choice over contextual alternatives, using information-theoretic notions of cost.We distinguish between goal-directed alternatives that realise a fixed communicative intent and goal-agnostic alternatives defined only by contextual plausibility, allowing us to derive speaker-and listener-oriented interpretations of different cost measures.We present a procedure to generate both types of alternative sets using language models.Analysing production choices in open-ended dialogue under both deterministic and probabilistic cost minimisation, we find that surprisal minimisation relative to goal-directed alternatives provides the strongest predictive account under both analyses.By contrast, uniform information density and length-based costs exhibit weaker and less consistent predictive power across conditions.More broadly, our study suggests that alternative-conditioned optimisation with LMgenerated alternatives provides a principled framework for studying speaker and listener pressures in naturalistic language production. 1