  We report upgraded Giant Metrewave Radio Telescope observations of the
massive merging galaxy cluster Abell 2744. The cluster is experiencing a very
complex multiple merger and hosts a giant halo and four radio relics. To study
the spectral and polarization properties, and radio versus X-ray correlations
of the diffuse sources, we complement our analysis with existing VLA and
Chandra observations. In our new images, the central halo emission is observed
to be more extended than detected previously. The integrated spectrum of the
halo follows a power-law between 150 MHz and 3 GHz, while its subregions show
significantly different spectra also featuring high frequency spectral
steepening. Our results highlight that an overall power-law spectrum, as
observed in many radio halos, may also arise from the superposition of
different subcomponents. The radio brightness distribution of the halo strongly
correlates with the X-ray brightness of the intracluster medium (ICM) with a
constant sublinear slope from 675 MHz to 3 GHz. The comparison of the spectral
index with the X-ray brightness and temperature reveals different trends,
indicating that the halo consists of two main components with distinct
evolutionary signatures. All four relics in this system follow a power-law
radio spectrum, compatible with shocks with Mach number in the range $3.0-4.5$.
All relics are also highly polarized between $1-4$ GHz and show Faraday
dispersion measures below $10 \rm rad m^{-2}$, suggesting that they are located
in the low density ICM. The complexity in the distribution and properties of
nonthermal components in Abell 2744 support a multiple merger scenario. Our
results demonstrate the importance of sensitive and high-resolution,
multi-frequency radio observations for understanding the interplay between the
thermal and non-thermal components of the ICM.
