This dissertation explores the expression of counterfactuality crosslinguistically , both from a morpho - syntactic / semantic perspective â focusing on the interaction between tense , aspect , mood and modality â and from a semantic / pragmatic perspective â focusing on the presuppositions and implicatures of counterfactual conditionals . Through special emphasis on Palestinian Arabic , this dissertation contributes an enlightening perspective on the typological dimension of counterfactuals . By offering a description and analysis of novel data , this dissertation shows that the relative morpho - syntactic transparency with which Palestinian Arabic expresses counterfactuals offers an illuminating view on puzzling crosslinguistic data . In doing so , this dissertation sheds light on and helps discriminate among existing accounts of counterfactuality . This dissertation also adds clarity to the semantic dimension of counterfactuals by proposing a compositional / dynamic account that might be crosslinguistically unifying for counterfactual conditionals and their use in context . This study is of interest to scholars concerned with issues related to the typology , syntax , and semantics of counterfactual conditionals , as well as those involved in the inquiry into the syntax / semantics interface in the tradition of Generative Grammar or those interested in Dynamic Semantics .