  We have investigated the structural, magnetic and dielectric properties of
Pb-based langasite compound Pb$_3$TeMn$_3$P$_2$O$_{14}$ both experimentally and
theoretically in the light of metal-oxygen covalency, and the consequent
generation of multiferroicity. It is known that large covalency between Pb 6$p$
and O 2$p$ plays instrumental role behind stereochemical lone pair activity of
Pb. The same happens here but a subtle structural phase transition above room
temperature changes the degree of such lone pair activity and the system
becomes ferroelectric below 310 K. Interestingly, this structural change also
modulates the charge densities on different constituent atoms and consequently
the overall magnetic response of the system while maintaining global
paramagnetism behavior of the compound intact. This single origin of modulation
in polarity and paramagnetism inherently connects both the functionalities and
the system exhibits mutiferroicity at room temperature.
