Various letters have been used to write the click consonants of southern Africa. The precursors of the current IPA letters, ⟨ǀ ǁ ǃ ǂ⟩, were created by Karl Richard Lepsius and used by Wilhelm Bleek and Lucy Lloyd, who added ⟨ʘ⟩. Also influential were Daniel Jones, who created the letters ⟨ʇ ʖ ʗ ʞ⟩ that were promoted by the IPA from 1921 to 1989, and used Clement Doke and .