A mixed language expression execution method and apparatus includes an execution engine equipped to determine whether an execution context has previously been created for an expression, upon receiving a request to execute the expression. If not, one is created, invoking one or more expression processors, to contribute to the initialization of the execution context. If created or upon creation, the expression (including its sub-expressions, if any) is executed, using the execution context. The result is then returned to the requester. In one embodiment, the execution context is object oriented, and includes various methods to facilitate the initialization and execution. Further, at least one expression processor includes a load and an execute interface equipped to use these methods.