  The search for exotic topological effects of phonons has attracted enormous
interest for both fundamental science and practical applications. By studying
phonons in a Kekul\'e lattice, we find a new type of pseudospins characterized
by quantized Berry phases and pseudoangular momenta, which introduces various
novel topological effects, including topologically protected
pseudospin-polarized interface states and a phonon pseudospin Hall effect. We
further demonstrate a pseudospin-contrasting optical selection rule and a
pseudospin Zeeman effect, giving a complete generation-manipulation-detection
paradigm of the phonon pseudospin. The pseudospin and topology-related physics
revealed for phonons is general and applicable for electrons, photons and other
particles.
