Chilean and River Plate voseo verb forms are derived from those corresponding to vosotros has been challenged as synchronically inadequate in a 2014 article, on the grounds that it requires at least six different rules, including three monophthongization processes that completely lack phonological motivation. Alternatively, the article argues that the Chilean and River Plate voseo verb forms are synchronically derived from underlying representations that coincide with those corresponding to the non-honorific second person singular tú. First, both Chilean and River Plate has an accentuation rule which assigns stress to the syllable following the verb's root, or its infinitive in the case of the future and conditional conjugations. This alone derives all the River Plate verb conjugations, in all tenses. Chilean verb forms also undergo rules of semi-vocalization, vowel raising, and aspiration. In semi-vocalization, becomes the semivowel when after ; thus, becomes , and becomes 'you are'. The vowel raising rule turns stressed into , so becomes . Aspiration, a normal part of Chilean, and River Plate, Spanish phonology, means that syllable or word-final becomes pronounced like an . The proposed theory requires the use of only one special rule in the case of Chilean voseo. This rule plus other rules that are independently justified in the language make it possible to synchronically derive all the Chilean and River Plate voseo verb forms in a straightforward manner. The article additionally solves the problem posed by the alternate verbal forms of Chilean voseo like the future indicative (e.g. bailaríh or 'you will dance'), the present indicative forms of haber (habíh and hai 'you have'), and the present indicative of ser (soi, eríh and eréi 'you are'), without resorting to any ad hoc rules. All these different verb forms would come from different underlying representations. The future forms and come from underlying and , the latter related to the historical future form in which was documented in Chile in the 17th century. and come from and , while and come from and . The form also comes from , with an extension of semi-vocalization. The theoretical framework of the article is that of classic generative phonology. Attitudes In some countries, the pronoun vos is used with family and friends (T-form), like tú in other varieties of Spanish, and contrasts with the respectful usted (V-form used with third person) which is used with strangers, elderly, and people of higher socioeconomic status; appropriate usage varies