In my previous post, I discussed the fact that 'flaming hot' uttered by a male speaker from Hong Kong was not understood by a female listener from Malaysia, mostly because this is not a common phrase in English.
In the same conversation, the Malaysian could not understand the speaker from Hong Kong when he used the phrase 'terminal degree', even though he said it quite clearly so there was nothing about the pronunciation that caused the problem.
In this case, the phrase 'terminal degree' is a common phrase in the United States to refer to the final degree one studies — it occurs 40 times in the COCA Corpus of American English. However, it is not a common phrase outside of the United States. I checked with my colleagues, and only one of them had heard it before.
This illustrates that problems of intelligibility can be affected by a range of different factors: not just pronunciation, but also familiarity with typical phrases that occur in the variety of English being spoken.