Assimilation and Disemulation

Disemulation is where something changes in order to be not the same as a sound. This happens in English, doesn't it? I can't think of an example in English. Can you start for one? Yes. There was a process in ancient Greek where if a dental stop ran into another dental stop, the first one turned into a fricative namely the S. And that process continued such that in modern Greek any final voiceless stop historically has become a voiceless fricative. So let's kind of move on. We've talked a long time on assimilation. Why don't we talk a little bit about assimilation and then keep going down on the different types so