Though Reverend Hale is trying to get Tituba to name her accomplices, who is the first person to actually mention names?
Yes, Abigail is, in fact, the first person to name names. As Reverend Hale questions her and her uncle, the Reverend Parris, she is forced to reveal a number of facts that make her look pretty bad: she was dancing in the forest, there was a kettle with liquid in it on the fire, and a "very little frog jumped" in. Finally, Hale "grasp[s]" her and tells her that her cousin may be dying. In desperation, it seems, she accuses the one person she knows will be believably guilty: Parris's slave, Tituba.
Tituba is then forced to admit that she gave Abby chicken blood to drink, and so the questions begin to focus more forcefully on her. As Abigail piles on the lies, Parris threatens to whip Tituba to death, and Putnam demands that she be hanged. In the midst of the accusations and threats, Hale begins to speak gently and softly to her, and she seems to want to give him the information he desires. She then names Sarah Good and Sarah Osburn, both women that Mr. Putnam had just named as potential witches a few moments earlier, knowing, it seems, that she will be believed since she names those who he already suspects. Abigail and Betty then pile on further accusations, naming some nine other individuals as witches as well.
The first person to start the accusations is Abigail, Betty Parris's cousin, who, ironically enough, had already stated that she would kill anyone who breathed a word of what had happened in the forest with Tituba. Abigail, pleasant young lady that she is, has been engaging in the funky spells as well as drinking chicken blood to try to kill Elizabeth Procter, the wife of the man with whom she once had an affair. After Abigail accuses Tituba of being a witch, the frightened Tituba professes her faith in God and then accuses the Goodwives Good and Osburn of witchcraft. Then Betty wakes up from her stupor, and she and Abigail proceed to provide a list of persons they claim to have seen with the Devil.