There is a new feature in Mountain Lion, Dictation.
When I try to enable it in the System Preferences, I get the following dialog:
In other words, what Dictation does is just record your voice and send it to Apple, which does the conversion of your voice into text server side. This makes very little sense on today's powerful laptop or desktop Macs (I can see why it would make sense on a mobile device though). Is there a way to use the Dictation feature offline?
Best Answer
No, your speech is still sent to the Siri/Nuance servers for processing, so you can't use dictation without an Internet connection.
An alternative would be to use a third-party dictation app like Dragon Dictate.
While your machine is probably powerful enough to handle conversion (although maybe not as quickly as Apple's servers), it makes a lot of sense for Apple to keep things on their end. The software used for conversion is doubtlessly quite complex and would be a huge download. Living on their servers also means that they can push updates as frequently and quickly as they like.