Siri on the iPhone 4S can understand a lot of instructions. Ask the virtual assistant to send a tweet to Twitter, however, and Siri will respond that it just can’t do that.

The truth is, however, that Siri can – you just have to be a bit sneaky. First, add a new contact on your iPhone. Make the first name Twitter, the phone number 86444 (Twitter’s SMS shortcode for the UK), and save the contact.

Next, send a text message to that number containing only the word start. You’ll get a reply with instructions on how to log into Twitter via text message. Once you finish texting your login credentials to Twitter, you can send tweets at any time by texting them to that number.

From now on, Siri can help you send tweets as if they were text messages. For example, trigger Siri and say, “Tell Twitter, ‘Hey! I wrote this tweet using my voice!’” Siri interprets your instruction as composing a text message, and after you confirm it, will send it to Twitter. You’ve tricked Siri into learning a new function.

Sorry about that… I’ll send tweets for you if you can convince me they’re really text messages

Bear in mind that, by default, Twitter will now want to text you about other Twitter goings-on, like new retweets or mentions. Active Twitter users who prefer to get their notifications through non-text means will want to visit their Twitter mobile settings and untick any unwanted options.