s : ▁ ▁(" che " ▁or ▁" ce ▁ha che "), ▁▁ ▁(" elle " ▁or ▁" do ble ▁ele "), ▁▁ ▁(" do ble ▁erre "), ▁▁ ▁(" ge ▁u ") ▁and ▁▁ ▁(" cu ▁u "). ▁While ▁che ▁and ▁elle ▁were ▁formerly ▁treated ▁each ▁as ▁a ▁single ▁letter , ▁in ▁ 1 9 9 4 ▁the ▁t enth ▁con gress ▁of ▁the ▁Association ▁of ▁Spanish ▁Language ▁Academ ies , ▁by ▁request ▁of ▁UN ES CO ▁and ▁other ▁international ▁organizations , ▁agreed ▁to ▁alphabet ize ▁ ▁and ▁ ▁as ▁ordinary ▁sequences ▁of ▁letters . ▁▁▁ ▁Thus , ▁for ▁example , ▁in ▁diction aries , ▁ch ico ▁is ▁alphabet ized ▁ ▁after ▁centro ▁and ▁before ▁ciudad , ▁instead ▁of ▁being ▁alphabet ized ▁after ▁all ▁words ▁beginning ▁with ▁cu - ▁as ▁was ▁formerly ▁done . ▁▁ ▁Despite ▁their ▁former ▁status ▁as ▁unit ary ▁letters ▁of ▁the ▁alphabet , ▁ ▁and ▁ ▁have ▁always ▁been ▁treated ▁as ▁sequences ▁with ▁regard ▁to ▁the ▁rules ▁of ▁capital ization . ▁Thus ▁the ▁word ▁ ▁in ▁a ▁text ▁written ▁in ▁all ▁caps ▁is ▁CH ILL Ó N , ▁not ▁* Ch IL l Ó N , ▁and ▁if ▁it ▁is ▁the ▁first ▁word ▁of ▁a ▁sentence , ▁it ▁is ▁written ▁Ch ill ón , ▁not ▁* CH ill ón . ▁Sometimes , ▁one ▁finds ▁lif ts ▁with ▁buttons ▁marked ▁, ▁but ▁this ▁double ▁capital ization ▁has ▁always ▁been ▁incorrect ▁according ▁to ▁R AE ▁rules . ▁ ▁This ▁is ▁the ▁list ▁of ▁letters ▁from ▁most ▁to ▁least ▁frequent ▁in