Most states differentiate between the charges of voluntary and involuntary manslaughter, depending on the defendant's actions and their effects. Texas makes no such distinction. Instead, additional penalties are imposed upon anyone found guilty of manslaughter under certain circumstances, such as when the act was committed while the defendant was in a state of intoxication.
However, Texas allows a wide variety of reasonable defenses against the charge of manslaughter. For example, self defense may be considered exculpatory in the case of manslaughter. If the defendant can demonstrate to the satisfaction of the court that they were defending themselves from a violent situation, and that they responded with an appropriate level of violence that caused the death of their assailant, then their conviction may be prevented.
Another legally recognized defense against manslaughter charges is proof that the fatal incident was an accident and that the defendant had not been careless, negligent, or acting with egregious bad conduct when the death occurred. If the defendant had been acting without criminal intent and had no reasonable way to know that their actions could lead to the death of another, then they may able to show this in court to avoid conviction.
An attorney's advice may be valuable to anyone who has been formally charged with criminal actions relating to the death of another. They may be able to lend their expertise to someone who is attempting to construct a defense that does not argue that the death did not occur, only that the defendant's actions are in some way excusable or without blame. They may also be able to help negotiate extremely serious charges such as murder or capital murder down to charges like manslaughter.