A person who unintentionally kills without justification commits involuntary manslaughter if his acts are performed ______, except in cases involving operating a motor vehicle.

Involuntary manslaughter pertains to the unintentional killing of another person that occurs during the commission of an unlawful act or as a result of criminal negligence. In the context of the question, the correct term is "recklessly." When one acts recklessly, they are aware of a substantial and unjustifiable risk that their actions could lead to death, yet they proceed anyway. This awareness and disregard for the risk sets the stage for involuntary manslaughter.

In Illinois law, recklessness demonstrates a level of culpability that distinguishes it from mere negligence. A person who acts recklessly shows a blatant indifference to human life, which is why their actions can result in involuntary manslaughter charges. The distinction is crucial; if one were merely negligent, the legal threshold for manslaughter may not be met.

In the context of the other choices, while acting angrily or while impaired could potentially lead to reckless behavior, they do not directly encapsulate the legal standards necessary for a finding of involuntary manslaughter. Similarly, "specially" does not relate to the legal definitions surrounding this crime, making recklessness the strict and appropriate criterion for this charge in most scenarios, except those specifically stated regarding motor vehicle operation.