Full Idea
The process is dubbed 'conversational implicature' when the inference is not from the content of what has been said, but from the fact that it has been said.
Gist of Idea
Inference not from content, but from the fact that it was said, is 'conversational implicature'
Source
Herbert B. Enderton (A Mathematical Introduction to Logic (2nd) [2001], 1.7.3)
Book Reference
Enderton,Herbert B.: 'A Mathematical Introduction to Logic' [Academic Press 2001], p.11