However, early in the history of the IPA, that letter had been used for the voiceless fricative, now written ⟨χ⟩, paralleling ⟨ᴙ ʀ⟩ for the voiceless and voiced trills.
Imidlertid blev det symbol tidligt i IPA's historie brugt for den ustemte hæmmelyd, nu skrevet ⟨χ⟩, med paralleller til ⟨ᴙ ʀ⟩ for de ustemte og stemte tremulanter.