Complex sentence: In the velar position, the tongue has an extremely restricted ability to carry out the type of motion associated with trills or taps, and the body of the tongue has no freedom to move quickly enough to produce a velar trill or flap.
Split into simpler sentences: In the velar position the tongue has an extremely restricted ability to carry out the type of motion associated with trills or taps. Nor does the body of the tongue have the freedom to move quickly enough to produce a velar trill or flap.