  Recently the question of phonon angular momentum has been raised : phonon
angular momentum in a magnetic crystal could play an important role in the
angular momentum balance in the Einstein-de Haas effect. This proposition is
quite natural and understandable, however the idea of phonon spin seems
ambiguous in the literature. In 1988 McLellan presented phonon angular momentum
states for circular and elliptical polarizations of phonons that represent
orbital angular momentum and also pointed out analogy to isotropic quantum
harmonic oscillator. In view of its fundamental importance we investigate this
issue and conclude that phonon spin hypothesis is physically untenable, and the
phonon angular momentum has to be interpreted as orbital. The photon-phonon
analogy is also misleading. It is argued that Cosserat elastic medium having
internal torque may have lattice excitations different from phonons having spin
one or spin two that we term as Cosseratons. In addition a new source of
angular momentum balance originationg from anomalous electron magnetic moment
is suggested.
