"Nativelike selection"

Work like the classic seminal work of Pawley and Syder demonstrate natural language is far from random, but is equally far from regular:

p.g. 2
"The problem we are addressing is that native speakers do not
exercise the creative potential of syntactic rules to anything like
their full extent, and that, indeed, if they did do so they would
not be accepted as exhibiting nativelike control of the language.
The fact is that only a small proportion of the total set of grammatical
sentences are nativelike in form - in the sense of being
readily acceptable to native informants as ordinary, natural forms
of expression, in contrast to expressions that are grammatical but
are judged to be 'unidiomatic', 'odd' or 'foreignisms'."

Pawley, A. and H. Syder. 1983. Two puzzles for linguistic theory: nativelike selection and nativelike fluency. In Language and communication, eds. J. Richards and R. Schmidt, London: Longman, pp. 191–226.

http://www.linguistics.uwa.edu.au/__data/page/74645/PawleySyder.pdf