Sj-sound

The sj-sound (Swedish: sj-ljudet [ˈɧêːˌjʉːdɛt]) is a voiceless fricative phoneme found in the sound system of most dialects of Swedish. It has a variety of realisations, whose precise phonetic characterisations are a matter of debate, but which often feature distinct labialization. The sound is represented in Swedish orthography by a number of spellings, the most common of which are ⟨sj⟩ (from which the common Swedish name for the sound is derived), ⟨stj⟩, ⟨skj⟩, and (before front vowels) ⟨sk⟩; if considered in complementary distribution with [ʂ], up to 65 different spellings for the phoneme have been identified in native words and loanwords. The sound should not be confused with the Swedish tj-sound /ɕ/, usually spelled ⟨tj⟩, ⟨kj⟩, or (before front vowels) ⟨k⟩.

The IPA letter for these sounds, ⟨ɧ⟩ (called Hooktop heng in the IPA Handbook), has occasionally been used for other languages, but as it has no set phonetic value, this is only useful as an abstraction (as indeed it is in Swedish).