  We propose a new model of leptons and quarks based on the discrete flavor
symmetry $T'$, the double covering of $A_4$, in which the hierarchies of
charged fermion masses and the mildness of neutrino masses are responsible for
Higgs scalars. After spontaneous breaking of flavor symmetry, with the
constraint of renormalizability in the Lagrangian, the leptons have $m_{e}=0$
and the quarks have the Cabibbo-Kobayashi-Maskawa (CKM) mixing angles
$\theta^{q}_{12}=13^{\circ}, \theta^{q}_{23}=0^{\circ}$ and
$\theta^{q}_{13}=0^{\circ}$. Thus, certain effective dimension-5 operators are
introduced, which induce $m_{e}\neq0$ and lead the quark mixing matrix to the
CKM one in form. On the other hand, the neutrino Lagrangian still keeps
renormalizability. For completeness, we show numerical analysis: in the lepton
sector, only normal mass hierarchy is permitted within $3\sigma$ experimental
bounds with the prediction of both large deviations from maximality in the
atmospheric mixing angle $\theta_{23}$ and the measured values of reactor
angle. So, future precise measurements of $\theta_{23}$, whether
$\theta_{23}\rightarrow45^{\circ}$ or
$|\theta_{23}-45^{\circ}|\rightarrow5^{\circ}$, will either exclude or favor
our model. Together with it, our model makes predictions for the Dirac CP
phase, which is almost compatible with the global analysis in $1\sigma$
experimental bounds. Moreover, we show the effective mass $|m_{ee}|$ measurable
in neutrinoless double beta decay to be in the range
$0.04\lesssim|m_{ee}|[eV]<0.11$, which can be tested in near future neutrino
experiments.
