Although to make things a little more complicated there is also a second ~かける suffix: e.g. 話しかける
This doesn't mean "to be in the midst of/half~" but is more like a directional/unilateral action (so 話す can be to talk with somebody, 話しかける to start up a conversation or address somebody).
Which dictionary do you use? A good dictionary should have these usages listed (and specified as verb-suffixes, separate from the standalone uses of かける).