as "grave" and articulatorily as "retracted"), with a weak "hushing" sound reminiscent of fricatives. In Andalusia, Canary Islands and most of Hispanic America (except in the Paisa region of Colombia) it is pronounced as a voiceless dental sibilant , much like the most frequent pronunciation of the /s/ of English. Because /s/ is one of the most frequent phonemes in Spanish, the difference of pronunciation is one of the first to be noted by a Spanish-speaking person to differentiate Spaniards from Spanish-speakers of the Americas. The phoneme , spelled , a palatal lateral consonant that can be approximated by the sound of the of English million, tends to be maintained in less-urbanized areas of northern Spain and in highland areas of South America. Meanwhile, in the speech of most other Spanish-speakers, it is merged with ("curly-tail j"), a non-lateral, usually voiced, usually fricative, palatal consonant, sometimes compared to English (yod) as in yacht and spelled in Spanish. As with other forms of allophony across world languages, the small difference of the spelled and the spelled is usually not perceived (the difference is not heard) by people who do not produce them as different phonemes. Such a phonemic merger is called in Spanish. In Rioplatense Spanish, the merged phoneme is generally pronounced as a postalveolar fricative, either voiced (as in English measure or the French ) in the central and western parts of the dialectal region (), or voiceless (as in the French or Portuguese ) in and around Buenos Aires and Montevideo (). Morphology The main morphological variations between dialects of Spanish involve differing uses of pronouns, especially those of the second person and, to a lesser extent, the object pronouns of the third person. Voseo Virtually all dialects of Spanish make the distinction between a formal and a familiar register in the second-person singular and thus have two different pronouns meaning "you": in the formal and either or in the familiar (and each of these three pronouns has its associated verb forms), with the choice of or varying from one dialect to another. The use of (and/or its verb forms) is called . In a few dialects, all three pronouns are used, with , , and denoting respectively formality, familiarity, and intimacy. In , is the subject form (, "you say") and the form for the object of a preposition (, "I am going with you"), while the direct