Abstract
This paper seeks to explore the possibility that Spanish intransitive verbs showing middle marking with no associated change of valency are a source of non-oppositional middle verbs. In order to do so, a study is conducted of the historical evolution of the middle-marked Spanish verbreír(se)‘to laugh’ as well as other semantically related verbs (such asalegrar(se)‘to be happy, pleased’, regocijarse ‘to rejoice’ andburlar(se), mofar(se), escarnecer(se) ‘to mock, to ridicule, to make fun of’), where the presence of the middle marker is associated with a valency-reducing diathesis.