A critical path in the development of natural language understanding NLU modules lies in the di culty of de ning a mapping from words to semantics: Usually it takes in the order of years of highly-skilled labor to develop a semantic mapping, e.g., in the form of a semantic grammar, that is comprehensive enough for a given domain. Yet, due to the very nature of human language, such mappings invariably fail to achieve full coverage on unseen data. Acknowledging the impossibility of stating a priori all the surface forms by which a concept can be expressed, we present Gsg: an empathic computer system for the rapid deployment of NLU front-ends and their dynamic customization by non-expert end-users. Given a new domain for which an NLU front-end is to be developed, two stages are involved. In the authoring stage, Gsg aids the developer in the construction of a simple domain model and a kernel analysis grammar. Then, in the run-time stage, Gsgprovides the enduser with an interactive environ...