I never noticed how subtly different Clark's two voices were
until Superman used his "Clark voice" when he'd been arrested, and how weird it looked coming from his mouth.
shareHis posture changes as well.
There was a latter 4 season episode where the Planet's new boss hits on Lois, so to cause contention between Lois and Clark. At their home, Clark is super upset with his Superman voice and hands gripping his waist.