  We proposed a generalized Lagrangian for three different classes of scalar
fields namely quintessence($\alpha =-1$), phantom($\alpha =0$), and tachyonic
($\alpha =1$) parameterized by $\alpha$. These three scalar fields can be
described by a common single Lagrangian called generalized scalar field
Lagrangian and corresponding scalar field termed as generalized scalar field.
We obtain mathematically consistent forms of generalized equations of motion
from which individual equations of motion of quintessence, phantom, and tachyon
can be recovered.
