d ▁in ▁the ▁Spanish ▁orth ography ▁are ▁, ▁ ▁( as ▁the ▁dig raph s ▁ ▁and ▁, ▁respectively ), ▁ ▁( only ▁when ▁they ▁represent ▁different ▁sounds : ▁e . g . ▁ac ción , ▁dic cion ario ), ▁ ▁( e . g . ▁inn ato , ▁per enne , ▁con not ar , ▁dí g ann os ), ▁and ▁ ▁( in ▁a ▁few ▁words ▁with ▁the ▁prefix ▁sub - : ▁sub base , ▁sub b ético ). ▁Exception s ▁to ▁this ▁limitation ▁are ▁g amma ▁( and ▁its ▁derivatives ▁g amm ag lob ul ina , ▁g amm ag raf ía ), ▁dig amma , ▁k appa , ▁at to -, ▁as ▁well ▁as ▁un ada pt ed ▁foreign ▁words ▁( including ▁proper ▁names ) ▁and ▁their ▁deriv ations ▁( see ▁below ). ▁ ▁V ow els ▁ ▁The ▁letter ▁Y ▁The ▁letter ▁ ▁is ▁consist ently ▁used ▁in ▁the ▁con son antal ▁value . ▁The ▁use ▁of ▁the ▁letter ▁ ▁for ▁a ▁v owel ▁or ▁a ▁sem iv owel ▁is ▁very ▁restricted . ▁The ▁di ph th ongs ▁ ▁are ▁usually ▁written ▁ ▁at ▁the ▁end ▁of ▁words ▁( e . ▁g . ▁hay , ▁le y , ▁voy , ▁muy ), ▁though ▁exceptions ▁may ▁occur ▁in ▁loan words ▁( e . g . ▁b ons á i , ▁ag n us d é i ). ▁The ▁letter ▁ ▁is ▁conser ved ▁in ▁rarely ▁used ▁en cl it ic ized ▁ver bal ▁forms ▁like ▁do y te ,