  We analyze the recent experimental evidence for an excess of $\tau$-lepton
production in several exclusive semileptonic $B$-meson decays in the context of
two-Higgs-doublet models. These decay modes are sensitive to the exchange of
charged scalars and constrain strongly their Yukawa interactions. While the
usual Type-II scenario cannot accommodate the recent BaBar data, this is
possible within more general models in which the charged-scalar couplings to
up-type quarks are not as suppressed. Both the $B\to D^{(*)}\tau\nu_\tau$ and
the $B\to\tau\nu_\tau$ data can be fitted within the framework of the Aligned
Two-Higgs-Doublet Model, but the resulting parameter ranges are in conflict
with the constraints from leptonic charm decays. This could indicate a
departure from the family universality of the Yukawa couplings, beyond their
characteristic fermion mass dependence. We discuss several new observables that
are sensitive to a hypothetical charged-scalar contribution, demonstrating that
they are well suited to distinguish between different scenarios of new physics
in the scalar sector, and also between this group and models with different
Dirac structures; their experimental study would therefore shed light on the
relevance of scalar exchanges in semileptonic $b\to c\,\tau^-\bar\nu_\tau$
transitions.
