But the undeniable experience of many many iPhone users is that you have probably seen the soft keyboard autocorrect to "duck" many times when you intended to w

But the undeniable experience of many many iPhone users is that you have probably seen the soft keyboard autocorrect to "duck" many times when you intended to write "fuck". The soft keyboard is always using some heuristics to identify which characters you intended to type. In most cases it's quite accurate, but in this case it seems like it's over-counting the probability you would have typed "duck" or "ducking" by a fairly wide margin.