As this power increases the ability of computers to handle spoken language well increases. As the market for this technology increases, the price of this technology decreases dramatically. Consistent and correct microphone position is one of the very most important factors in successful speech recognition with a computer. Consistent volume, not consistent intonation, is also a very important factor in successful speech recognition with a computer. Speaking naturally means not speaking the way you think you should, but rather speaking the way you actually do.
Most people become significantly self-conscious when speaking to a computer.
They say words in unaccustomed ways, which it turns out, they cannot repeat later. Speaking clearly simply means actually saying each word you intend to say. Many people actually slur over so many words that they actually say quite a few fewer than they think they do. Overt enunciation will dramatically hurt speech recognition. But so will leaving out great chunks of the words.