  Zipf's law in the field of linguistics is tested in the nuclear disassembly
within the framework of isospin dependent lattice gas model. It is found that
the average cluster charge (or mass) of rank $n$ in the charge (or mass) list
shows exactly inversely to its rank, i.e., there exists Zipf's law, at the
phase transition temperature. This novel criterion shall be helpful to search
the nuclear liquid gas phase transition experimentally and theoretically. In
addition, the finite size scaling of the effective phase transition temperature
at which the Zipf's law appears is studied for several systems with different
mass and the critical exponents of $\nu$ and $\beta$ are tentatively extracted.
