  The presence of twist angles between layers of two-dimensional materials has
a profound impact on their physical properties. Turbostratic multilayer
graphene is a system containing a distribution of rotational stacking faults,
and these interfaces also have variable twist angles. In this work, we examine
the influence of turbostratic single-layer graphene content on the in-plane
thermal conductivity of a defect free multilayer graphene system with low
defect density. Detailed Raman mode analysis is used to quantify the content of
turbostratic single-layer graphene in the system while complementing insight is
obtained from selected area electron diffraction studies. Thermal transport in
these systems is investigated with Raman optothermal technique supported with
finite element analysis simulations. Thermal conductivity of AB-stacked
graphene diminishes by a factor of 2.59 for 1% of turbostratic single-layer
graphene content, while the decrease at 19% turbostratic content is by an order
in magnitude. Thermal conductivity broadly obeys the relation, $\kappa$
$\propto$ exp(-F), where F is the fraction of turbostratic single-layer
graphene content in the system
