وأهلها متبربرون وأكثرهم يتكلّم باللسان اللطيني الإفريقي.He even gives one word of their dialect:
Its inhabitants are Berberised, and most of them speak the African Latin tongue.
ولها في وسطها العين المسماة بالطرميد.One interesting thing to note about this statement is that he said that the town was Berberised - in other words, that, in the very century when the Banū Hilāl were rapidly spreading through Tunisia and Libya (a subject he has fairly harsh things to say about), Berber culture was prestigious enough to be adopted by members of other cultures, in particular the remaining Roman or Romanised towns, in the area. Gafsa, of course, speaks Arabic now, but several nearby villages still spoke Berber in the 1800s, and two, Sened and Majoura, well into the 1900s.
In the middle of the town is a spring called the ṭarmīd (perhaps to be related to Latin thermae).