Scott Schwenter 
Pragmatics of Conditional Marking [PDF ebook] 
Implicature, Scalarity, and Exclusivity

First Published in 1999. This book investigates the meaning of conditional protasis markers like Spanish si ”if” and English if from a pragmatic perspective. A standard assumption in linguistics is that these words encode as part of their semantics notions like hypothetical, irrealis, or, from the speaker”s point of view, uncertain, as in constructed examples like (la), where speaker B is unsure whether the proposition she”s eating is true or not.