If the multiply determined response is completely affected by a formal source, then the strengthening is NOT fragmentary. If you say “no smoking” both because it would be currently reinforcing to you if someone nearby stopped smoking and also because you faintly heard someone say “no smoking,” the echoic source would not be considered fragmentary.
A type of stimulus control with the following features:
The response form is multiply controlled
At least one of the controlling variables strengthens only one part of the response form
Which types of elementary verbal relationships are involved
The response topography