In fact, the question is not as simple as that. It raises a lot of issues that are not simply technical things. For example, what would you consider as «intelligent»? what do you define as a «verbal conversation with the average English-speaking human»?
The question of intelligence is still open and more philosophical:
- is a computer, being able to make complex calculus more intelligent than a human?
- Or is the intelligence something less tangible, like the conscience of the self and so on...
Personally, I think it is really hard to say if a computer will ever be «intelligent» as we consider human to be intelligent. Computers are tools, the question for me is there efficiency.
For instance, intelligence in a conversation is hard to define. Let see what can be said about the intelligence and efficiency of a computer dialogue.
First, there is the question of the speech interface: speaking to the computer versus typing on the keyboard. In fact, speech recognition is already working — almost — fine and it is not a problem for the computer to translate the sound you make into a written text. And generating sound from a written text is not a difficulty for the computer either. This task needs no «intelligence» from the computer.
So lets now think about the conversation as understanding the content of what the human says and formulating a proper answer — grammatically correct sentence for instance.
In a sense, a computer can already have a conversation with a human. Take for example the AliceBot project you can «chat» with the computer and it sounds quite ok. However, the bot shows no intelligence: it only uses patterns to generate an answer. In fact it has no understanding of what is said. The proof is it’s mindlessness, you can change subject or say inconsistent things without it noticing.
Other systems are less generous in the conversation but can seem more intelligent, for example the train or plain phone reservation systems. They use basic dialogue rules to ask the user what they need to know to make the reservation. But there is no more intelligence there, it’s like google but with a natural language interface: there is no difference if you say "I want to go to New York the 3rd at 3pm" or "New York 3rd 3pm". The computer fills in the search fields for you, that’s it.
So as a conclusion, I am not sure how to answer your question. It could be «right now » as it could be «never».
