  We discuss the acceleration of secondary muons, pions, and kaons in gamma-ray
bursts within the internal shock scenario, and their impact on the neutrino
fluxes. We introduce a two-zone model consisting of an acceleration zone (the
shocks) and a radiation zone (the plasma downstream the shocks). The
acceleration in the shocks, which is an unavoidable consequence of the
efficient proton acceleration, requires efficient transport from the radiation
back to the acceleration zone. On the other hand, stochastic acceleration in
the radiation zone can enhance the secondary spectra of muons and kaons
significantly if there is a sufficiently large turbulent region. Overall, it is
plausible that neutrino spectra can be enhanced by up to a factor of two at the
peak by stochastic acceleration, that an additional spectral peaks appears from
shock acceleration of the secondary muons and pions, and that the neutrino
production from kaon decays is enhanced. Depending on the GRB parameters, the
general conclusions concerning the limits to the internal shock scenario
obtained by recent IceCube and ANTARES analyses may be affected by up to a
factor of two by secondary acceleration. Most of the changes occur at energies
above 10^7 GeV, so the effects for next-generation radio-detection experiments
will be more pronounced. In the future, however, if GRBs are detected as
high-energy neutrino sources, the detection of one or several pronounced peaks
around 10^6 GeV or higher energies could help to derive the basic properties of
the magnetic field strength in the GRB.
