The argument for telling the truth can be supported by the fairytale of Pinocchio (the boy in the picture). Every time Pinocchio told a lie, his nose grew and each time he told a lie, he seemed to get himself deeper and deeper in a mess trying to cover up each lie with another lie. Basically, telling a story that isn't true can sometimes be really quite difficult and as my nanna used to argue, you have to have a good memory to be a good liar. Each lie can lead to another and all have to fit together to make sense.
In terms of the speaking exam then, if you do decide to tell a story that isn't true, just remember, it will need to make sense and fit together so will require you to have a good imagination and a good memory to recall what you said if the examiner questions you on it.
So, perhaps it would be easier to simply tell the truth? When we tell the truth of what happened we can visualise the story in our minds because we were there and we only have to put words to the images as opposed to creating them from our imagination. This requires one less task, meaning we can focus more on our language use than on creating an imagined event. This seems like a simple solution.
However, as my friend pointed out, what do you do when the examiner asks you 'What did you do last weekend?' and the reality is that all you did was sleep and watch TV? Replying 'I slept and watched TV" might not provide much space or opportunity to show the examiner everything you know. So, should we lie in this case? Well, perhaps you could bend the truth a little by telling them about another weekend you had, which was much more interesting than last weekend - for example, the weekend you went to a different city to visit your friends or the weekend there was a festival in your local village.... It doesn't have to be last weekend exactly! Alternatively, you could elaborate on the watching TV and sleeping weekend:
- why did you sleep so much?
- what had you done that week to make you so tired?
- what did you watch on TV?
- what was interesting about the programmes?
- were they the programmes you normally watch?
- what do you think about TV in your country?
and so on....
Just because an initial answer might seem boring and you might think there is not much to say about it, a little bit of reflection can show you that actually, there could be plenty to say. And still, saying all of this, which is what actually happened, will be easier than trying to create it in the moment in your head.
As the IELTS speaking is supposed to be as natural as possible, I think we would all agree that retelling a story that actually happened in our everyday life is much easier than trying to invent one at the time of speaking. So, in conclusion, try to stick to the truth if you can but don't be afraid to 'bend the truth' occasionally if you feel it will provide you with a fuller answer.
Vocabulary
fairytale (n) = story
nanna (n) = grandmother
visualise (v) = see, imagine
elaborate (v) = say more about, give more detail
initial (adj) = first
plenty (n) = enough, adequate amount
stick to (v) = stay close to, keep to