lexical unit and has no influence on a language's overall morphological or syntactic ergativity. For some of these verbs, native speakers' intuition tells us these words are primarily transitive and secondarily intransitive (such as smash or extend). For other words, the opposite is true (trip, explode, melt, dissolve, walk, march). This latter group can be said to undergo change into a causative verb. Pseudo-reflexivity Alternating ambitransitives are not uncommon in English. In the Romance languages, such verbs are rarely found, since the same semantic concept is covered by pseudo-reflexive verbs. These verbs behave like ambitransitives, but the intransitive form requires a clitic pronoun that usually serves also for reflexive constructions. See for example, in Spanish (which uses the pronoun se in the third person): La ventana se rompió. "The window broke." Este barco se está hundiendo. "This boat is sinking." Se derritió todo el helado. "All of the ice cream melted." In the example, the verbs romper, hundir and derretir are all transitive; they become intransitive by using the pseudo-reflexive clitic, and the direct object becomes the intransitive subject. Ambiguity may arise between these and true reflexive forms, especially when the intransitive subject is animate (and therefore a possible agent). Me estoy hundiendo usually means "I'm sinking" (patientive first person), but it could also mean "I'm sinking myself", "I'm getting myself sunk" (agentive). See also Diathesis alternation Valency (linguistics) Transitivity (grammar) References External links Changing valency: Case studies in transitivity (edited by R. M. W. Dixon & A. Y. Aikhenvald, Research Centre for Linguistic Typology, La Trobe University, Melbourne) Transitivity and valency fr:Transitivité (grammaire)#Verbes labiles