  The normal state of cuprate superconductors exhibits many exotic behaviors
qualitatively different from the Fermi liquid, the foundation of condensed
matter physics. Here we demonstrate that non-Fermi liquid behaviors emerge
naturally from scattering against an emergent Bose liquid. Particularly, we
find a finite zero-energy scattering rate at low-temperature limit that grows
linearly with respect to temperature, against clean fermions' generic
non-dissipative characteristics. Surprisingly, three other seemingly unrelated
experimental observations are also produced, including the well-studied "kink"
in the quasi-particle dispersion, as well as the puzzling correspondences
between the normal and superconducting state. Our findings provide a general
route for fermionic systems to generate non-Fermi liquid behavior, and suggest
strongly that by room temperature the doped holes in the cuprates have already
formed an emergent Bose liquid of tightly bound pairs, whose low-temperature
condensation gives unconventional superconductivity.
