The problem of employing linguistic variables to rank alternatives across a set of criteria is investigated, with emphasis placed on modelling the decision-maker's reasoning process. Given a set of alternatives, decision-makers often do not make conclusions immediately, instead evaluating them in the light of a given set of criteria and then synthesizing the knowledge obtained from the evaluation. Both evaluation and synthesis are usually expressed linguistically rather than numerically. A fuzzy mathematical model is employed to represent this sort of linguistic evaluation and synthesis. An example is presented to illustrate the basic idea and technique. This example is also used to compare the proposed technique with another existing technique. The model can be employed in expert systems for making inferences on multi-criteria problems.