- phonological processing
- morphological processing
- syntactic processing
Such terms need to be followed by phrases such as "___ in the context of task ..." or something similar. To use these terms alone is meaningless. David tried to point this out back in 1996:
Poeppel, D., A critical review of PET studies of language. Brain and Language, 1996. 55: p. 317-351
(PET studies? What's that? Dude, you're old, ha!) The point was that the pattern of neural activity varies depending on what task is used to measure "x processing". This point was again underlined in each of the Hickok and Poeppel papers. Yet, I still see people saying things like "Broca's area activity is strongly correlated with phonological processing ability". That's kind of like the language equivalent of saying V5/MT activity is strongly correlated with visual processing. Ok, true in some cases, but not in others and even when it is true the statement isn't very helpful in the context of understanding neural circuits for information processing.
Sixteen years after David's 1996 paper (dude, you're old!) we know a little bit more about how language is organized in the brain. The circuits that are involved in x processing vary depending on whether the task is production or comprehension based, whether the materials are written or spoken, whether the task requires conscious attention to x or is more automatic, and so on. There's no excuse for using vague terminology anymore. It's just muddling the field.