Huh? I've been pronouncing sushi as it is... same for Shinjiku @.@
People mistaking those?
There's a transliteration method for japanese into romaji called kunrei-shiki where "shi" is "si", "chi" is "ti", "tsu" is "tu", "zu" is "du", "ji" is "zi", "cha" "chu" "cho" are "tya" "tyu" "tyo", and other annoyances.
It was adopted as the official way to transliterate japanese over Hepburn in 1937 because it's purely japanese created and has been the bane of people trying to learn japanese from shitty textbooks/resources that use it ever since. Official JSL lessons use it but resources that actually want people to learn japanese and know how learning works, like Genki, use Hepburn.