The Gemara discusses why these two acts might be considered separately when they are mentioned in the Torah together. Reish Lakish suggests that there is a different between the action of making sounds through one's armpit and simply moving one's lips. Rabbi Yochanan says that they should be considered together. The rabbis discuss whether or not there is a difference between these small actions and other small actions, including blasphemy. The rabbis question what "action" means. For example, is a spoken voice an action? This is particularly import in a system that relies on actions to define numerous legal realities.
The Gemara describes a witch as one who speaks words of the dead through a joint, like a knee joint. A wizard is one who places a bone in his or her mouth, and then the bone speaks words of the dead on its own. The rabbis argue about whether, from where, and how a skull might answer questions in 'normal' situations. Might a 'normal' skull avoid joining the community on Shabbat? A humorous argument arises regarding what makes Shabbat special - what makes one person special?
The rabbis tell stories of people making efforts to speak with the dead and then overcoming that urge to know the future. In one case, a demon is created and then dissolved. The Gemara discusses magicians and superstitious behaviour as well.
We know well that ancient and modern Jewish communities have embraced both halacha and other illicit behaviours that allow us to feel in control of the future. Although the rabbis have explicitly forbidden these behaviours - witchcraft, magic, wizardry, superstitions, etc - we have actively sought them out.