What is a question about this article? If the question is unanswerable, say "unanswerable".

Since the early 1960s, theoretical linguists have moved away from the traditional concept of a phoneme, preferring to consider basic units at a more abstract level, as a component of morphemes; these units can be called morphophonemes, and analysis using this approach is called morphophonology.

On what level do theoretical linguists consider basic approaches?
unanswerable