“…The vast, still growing literature on this topic has made clear that the factors that account for null and overt pronominal subjects are far more complex than the traditional explanations that can be found in reference grammars. According to, for example, the grammars of Butt and Benjamin (2013), Batchelor and San José (2010) and Kattán-Ibarra and Howkins (2014), recurrent factors that determine the use of a subject pronoun are emphasis, disambiguation and contrast. While especially contrastive uses and disambiguation are uncommon in natural data (Posio 2013: 256), studies like that of Enríquez (1984), Davidson (1996), Lipski (2002), Aijón Oliva andSerrano (2010), Travis andTorres Cacoullos (2012) and several publications of Posio (2011Posio ( , 2013Posio ( , 2014 have shown that grammatical factors such as person, mode and tense, the semantic category of verb, semantic roles, pragmatic weight (a speech act reading), priming (perseveration), particular formulaic constructions, the discourse type, as well as regional variation can explain the choice for a null or an explicit subject pronoun.…”