To execute a cursed speech, the user must use a cursed tool with a particular set of seals on it. For example, Toge Inumaki has seal markings on his cheeks and tongue. The Serpent Eyes and Fang tool created by the Inumaki family and used by Yuta Okkotsu also has similar seals. 
Cursed speech is activated when the user says words or commands aloud that are reinforced with cursed energy.. This action compels the listener to act or be acted upon as a command. For example, a cursed speech user can command his opponent to stop moving, or for them to be crushed. The strength of the compulsion depends on the skill level of the user.
The primary strength of cursed speech is its immense versatility due to its techniques being based on language. It is also effective against any opponent. Anyone unaware of how to defend against cursed speech is helpless against the user's words.
Like most cursed techniques, overusing cursed speech takes a physical toll on the user's body. The stronger the commands used, the worst the side effects are. In the worse case, cursed speech can backfire on the user and result in sore throats, coughing up blood, and/or losing the ability to speak. Many of these symptoms can be remedied with cough syrup or cough medicine.
Cursed speech is volatile in nature and can make it dangerous to speak with others. Civilians and anyone within the range of the user will be affected. As a countermeasure, users of cursed speech tend to limit their casual language to certain sage words that avoid triggering cursed speech. While this affects their day-to-day life of talking with others, it helps prevent unnecessary hazards. As a side effect, cursed speech users tend to be reserved individuals who use coded language due to their inability to converse naturally with others.
Jujutsu sorcerers can protect themselves from a cursed speech by manipulating the flow of cursed energy to their brain's section that controls ear function. This allows them to prevent words and commands from the cursed speech from being registered and executed.