If you have subscribed to Voicemail to Text transcription, you can compose a tweet just by speaking into your phone.
Follow these steps to tweet from voicemail.
1. From your voicemail Inbox, tap the Compose menu option . You will now be prompted to select the type of message to compose.
2. Select Transcribe to Twitter. An on-screen prompt to "Speak now" appears.
Note: This option will appear only if you have subscribed to Voicemail-to-Text transcription. It will not be available otherwise.
3. Speak your tweet. When you have finished speaking, the Visual Voicemail application will display a transcription.
4. If you want to edit the transcription before sending, tap the transcribed text. (The on-screen keyboard will appear.)
5. When you are satisfied with the text, tap Send to tweet it.