[1] FCG is an open instrument that can be used by construction grammarians who want to formulate their intuitions and data in a precise way and who want to test the implications of their grammar designs for language parsing, production and learning.
FCG integrates many notions from contemporary computational linguistics such as feature structure and unification-based language processing, but uses them in a novel way to operationalize insights from construction grammar theory.
FCG is called 'fluid' because it acknowledges the premise that language users constantly change and update their grammars.
If a match is successful, the FCG engine will "merge" all of the units of feature-value pairs with the transient structure in a similar unification-based process.
FCG features a meta-layers of diagnostics, repairs and consolidation strategies that allow the grammar designer to implement ways to handle novelty, errors and unexpected input during processing.