Talking about Google, A Google representative has confirmed to TechCrunch that iPhone owners will in fact be able to use text messaging and navigation features with Glass. The representative noted that Glass will work independently of the device it's connected to, and it's an affirmation of a statement made by Google earlier in the year. Currently, Glass wearers can only use the full set of features with an Android smartphone with the MyGlass companion app.
Frederic Lardinois makes clear that Glass doesn't have its own connection to the Internet to use such features, but will rather tether off of your smartphone to access data and pull in relevant information.
In this context, it’s worth noting that one of the myths surrounding Glass is that it is independently connected to the Internet. That’s not true, however. Instead, Glass users need to have a tethering plan for their phones to connect Glass to the Internet. In the eyes of your wireless provider, Glass is just another device that uses your phone’s personal hotspot feature.
Also keep in mind that at least on iOS, text messaging won't work with Apple's iMessage service. Instead, Glass will likely integrate with Google's rumored messaging service, Babel.