Wii Speak's retail availability is being curtailed and, if demand for it doesn't improve - which doesn't appear at all likely - Nintendo will phase out the microphone peripheral completely.
In a statement, Nintendo has confirmed Wii Speak's limited retail availability as part of a phasing out of it altogether. However, the company that it'll make additional shipments if demand for it improves.
Wii Speak enables voice communication with an entire room full of participants, rather than everyone using a headset. So this isn't the end of all voice communication on the console. Nintendo's statement suggested the licensed Headbanger Headset from Performance Designed Products as a chat substitute on the Wii, useful in games like Call of Duty: Black Ops and the upcoming The Conduit 2.
There was no word on the fate of the Wii Speak Channel, however.