What is the role of a strong acid catalyst in an elimination reaction?

An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism. The one-step mechanism is known as the E2 reaction, and the two-step mechanism is known as the E1 reaction.

Another definiton is;

Elimination reaction, any of a class of organic chemical reactions in which a pair of atoms or groups of atoms are removed from a molecule, usually through the action of acids, bases, or metals and, in some cases, by heating to a high temperature. It is the principal process by which organic compounds containing only single carbon-carbon bonds (saturated compounds) are transformed to compounds containing double or triple carbon-carbon bonds (unsaturated compounds).

Strong Acids play two key roles in elimination reactions:

1. Without the acid catalyst, the reaction is painfully slow.

2. Acid greatly facilitates elimination of the leaving group.