S
⟨sc⟩ is used in Italian for /ʃː/ before the front vowel letters e, i. It is used for /s/ in Catalan, French, English, Latin American Spanish, Occitan and Portuguese (e.g. French/English reminiscence, Latin American Spanish reminiscencia, Portuguese reminiscência, Catalan reminiscència, Occitan reminiscéncia).
⟨sç⟩ is used in French for /s/ in a few verb forms such as simple past acquiesça /akjɛsa/. It is also used in Portuguese as in the imperative form of verbs ending with scer: crescer cresça.
⟨sg⟩ is used in Piedmontese for /ʒ/.
⟨sh⟩ (see article; see also ſh⟩ below, which has the capitalized forms SH and ŞH)
⟨si⟩ is used in English for /ʒ/ in words such as fusion.
⟨sj⟩ is used Swedish to write the sje sound /ɧ/ (see also ⟨sk⟩) and in Faroese, Danish and Norwegian to write Voiceless postalveolar fricative /ʃ/.
⟨sk⟩ is used in Swedish to write the sje sound /ɧ/. It takes by rule this sound value before the front vowels (e, i, y, ä and ö) word or root initially (as in sked (spoon)), while normally representing in other positions. In Norwegian and Faroese, it is used to write voiceless postalveolar fricative /ʃ/ (only in front of i, y, ei and øy/oy).
⟨sl⟩ is used in the Iraqw and Bouyei languages to write the lateral fricative /ɬ/. (Sl is used in the French tradition to transcribe /ɬ/ in other languages as well.)
⟨sp⟩ is used in German for /ʃp/ as in Spaß instead of using schp (or chp).
⟨sr⟩ is used in Kosraean for /ʂ/.
⟨ss⟩ is used in Pinyin for /z/ in languages such as Yi. In other languages, such as Catalan, French, Italian, Occitan, Portuguese and Central Alaskan Yup'ik, where s⟩ transcribes /z/ between vowels (and elsewhere in the case of Yup'ik), ⟨ss⟩ is used for /s/ in that position (/sː/ in Italian). In romanized Korean, it represents the fortis sound /s͈/.
⟨st⟩ is used in German for /ʃt/ as in Stadt instead of using scht (or cht). In some parts of northern Germany, the pronouncation /st/ (as in English) is still quite common in the local dialect.
⟨sv⟩ is used in the Shona language to write the whistled sibilant /s͎/. This was written ȿ from 1931 to 1955.
⟨sx⟩ in used in Nambikwara for a glottalized /sʔ/, and in Esperanto as an unofficial surrogate of ⟨ŝ⟩.
⟨sy⟩ is used to write the sound /ʃ/ in Malay.
⟨sz⟩ (see article)
⟨s-c⟩ and ⟨s-cc⟩ are used in Piedmontese for the sequence /stʃ/.
⟨s-g⟩ and ⟨s-gg⟩ are used in Piedmontese for the sequence /zdʒ/.
Read more about this topic: Lj (digraph)