iOS 8 Voice Messaging

Your using the wrong Mic button for Siri translation

Your hitting the wrong button...
in iOS 8 when using SMS, you can either type a message in the white rectangular box to the right of the camera icon, tap the Mic to the right of the rectangular message box to speak a message or tap into the message box and then select the mic icon in the keyboard as it's always been to dictate via Siri.

Also if you tap the mic icon (right of the message box) speak your message while holding it down sliding up,when finished sends it off.
You have an option to tap beneath the message sent by hitting the word "Keep" in blue. This keeps the message in your history of the particular chat until the whole message chat is deleted.

Also I don't know how you guys are sending accidental voice messages, when you have to hold down the icon while speaking to send a voice message in the first place.
If you only tap it a message pops up in the window statig "Tap and hold to record and send audio".

If you hold the button down and speak or don't say anything, the message records and hangs open waiting for you to either slide up to send or tap the X to delete it instantly.

So to send ten minute or even brief messages, you would have to hold the mic icon and say your message, then slide upwards to send it. There's not an automatic send as it is now.

 

The voice messaging in iOS 8 has a similar raise to speak/listen ability like Siri. Generally you simply lock/turn off the screen before putting the phone somewhere which would avoid that. Aside from that there's a setting for voice messages in the Messages app as of iOS 8 beta 2 where you can enable/disable the raise to speak/listen part.