  In this work, the production processes of heavy neutral scalar and pseudo
scalar associated with standard model gauge boson $Z_L$ at future $e^{+}e^{-}$
colliders (ILC and CLIC) are examined. The total and differential cross
sections are calculated for the processes in the context of the littlest Higgs
model. Also dependence of production processes to littlest Higgs model
parameters in the range of compatibility with electroweak precision
measurements and decays to lepton flavor violating final states are analyzed.
We have found that both heavy scalar and pseudoscalar will be produced in
$e^+e^-$ colliders. Also the depending on the model parameters, the neutral
heavy scalar can be reconstructed or lepton flavor violating signals can be
observed.
