differentiate homophones, such as mi (my), and mí (me). In such cases, the accent is used on the homophone that normally receives greater stress when used in a sentence. Lexical stress patterns are different between words carrying verbal and nominal inflection: in addition to the occurrence of verbal affixes with stress (something absent in nominal inflection), underlying stress also differs in that it falls on the last syllable of the inflectional stem in verbal words while those of nominal words may have ultimate or penultimate stress. In addition, amongst sequences of clitics suffixed to a verb, the rightmost clitic may receive secondary stress, e.g. búscalo ('look for it'). Alternations A number of alternations exist in Spanish that reflect diachronic changes in the language and arguably reflect morphophonological processes rather than strictly phonological ones. For instance, a number of words alternate between and or and , with the latter in each pair appearing before a front vowel: Note that the conjugation of most verbs with a stem ending in or does not show this alternation; these segments do not turn into or before a front vowel: There are also alternations between unstressed and and stressed (or , when initial) and respectively: Likewise, in a very small number of words, alternations occur between the palatal sonorants and their corresponding alveolar sonorants (doncella/doncel 'maiden'/'youth', desdeñar/desdén 'to scorn'/'scorn'). This alternation does not appear in verbal or nominal inflection (that is, the plural of doncel is donceles, not *doncelles). This is the result of geminated and of Vulgar Latin (the origin of and , respectively) degeminating and then depalatalizing in coda position. Words without any palatal-alveolar allomorphy are the result of historical borrowings. Other alternations include ~ (anexo vs anejo), ~ (nocturno vs noche). Here the forms with and are historical borrowings and the forms with and forms are inherited from Vulgar Latin. There are also pairs that show antepenultimate stress in nouns and adjectives but penultimate stress in synonymous verbs (vómito 'vomit' vs. vomito 'I vomit'). Phonotactics Spanish syllable structure can be summarized as follows; parentheses enclose optional components: (C1 (C2)) (S1) V (S2) (C3 (C4)) Spanish syllable structure consists of an optional syllable onset, consisting of one or two consonants; an obligatory syllable nucleus, consisting of a vowel optionally preceded by and/or followed by a semivowel; and an optional syllable coda, consisting of one or two consonants. The following restrictions apply: Onset First