On Apple's website, it details how their voicemail transcription is limited to voicemails in English received on an iPhone with iOS 10 operating system or later, and the transcription "depends on the quality of the recording".
Peter Bell, a professor of speech technology at the University of Edinburgh, listened to the message left for Mrs Littlejohn.
He suggested it was at the "challenging end for speech-to-text engines to deal with".
He believes there are a number of factors which could have resulted in rogue transcription:
"All of those factors contribute to the system doing badly, " he added. "The bigger question is why it outputs that kind of content.
"If you are producing a speech-to-text system that is being used by the public, you would think you would have safeguards for that kind of thing."