I've been teaching ESL for over 30 years, but for the last three I've had almost exclusively Japanese students (I teach mostly 1-on-1 classes over Skype, to students from High School to Business Executives.) I'm also a professional linguist and somewhat of a hyperglot, but very much still a dilettante when it comes to Japanese. My question is this:
Is there any way using kana to represent the unpalatalized /s/ before /i/ or /ɪ/? When Japanese students read /si/, most of them invariably pronounce /ʃi/ because... well, you know why. I have many workarounds and ways of demonstrating the difference, but I thought it might be a truckload easier if there were a way of demonstrating this unequivocally so that when they saw it, the light would go on immediately.