What is a good way of implementing "next-word prediction"? For example, the user types "I am" and the system suggests "a" and "not" (or possibly others) as the next word. I am aware of a method that uses Markov Chains and some training text(obviously) to more or less achieve this. But I read somewhere that this method is very restrictive and applies to very simple cases.

I understand basics of neural networks and genetic algorithms(though have never used them in a serious project) and maybe they could be of some help. I wonder if there are any algorithms that, given appropriate training text(e.g., newspaper articles, and the user's own typing) can come up with reasonably appropriate suggestions for the next word. If not (links to)algorithms, general high-level methods to attack this problem are welcome.