This morning, I was listening to presentations from three of my students who have been on attachment with Royal Brunei, and the following sentence was mentioned:
We would like everyone to fasten your seatbelts.
How should you pronounce 'fasten'? Standard pronunciation is [fɑːsən] (or [fæsən] for American English); but my student pronounced it as [fɑːstən] with a [t], using what might be called spelling pronunciation. (See here for more on spelling pronunciation.)
The Longman Pronunciation Dictionary (Wells, 2008) does not list this possibility with a [t], even as a non-standard variant. But does that make it wrong? My guess is that it is quite common in this region, and it is probably more easily understood than the standard pronunciation, especially for people from China, Japan and Korea. If that is the case, then pronunciation with a [t] should be encouraged, even if it is not standard. Intelligibility is the key, never mind what dictionaries suggest.
Similarly, 'often' traditionally had no [t], but now it does for 27% of speakers in the UK and 22% in the USA (Wells, 2008, p. 560); and my guess is that this number is increasing, so that use of [t] in 'often' will soon become the norm. I also predict that 'fasten' will follow suit one day, and maybe 'listen' and 'castle' as well. Listening pronunciation is a well-established trend; so Royal Brunei cabin attendants who have a [t] in 'fasten' may be at the forefront of changing pronunciation.
