The International Phonetic Alphabet descends from Lepsius's Standard Alphabet through a simplification chain — Ellis's Palaeotype, then Sweet's Romic — with each step trading completeness for teachability

Although Lepsius's Standard Alphabet failed to spread, it fed forward into the notation that eventually succeeded. Wikipedia's Standard Alphabet entry credits it as "influential in later projects such as Ellis's Paleotype," and several of its conventions — the acute accent for palatalization, the under-dot for retroflex, the underline for Arabic emphatics, and its click letters — persist in modern phonetic use. Alexander John Ellis's Palaeotype in turn fed Henry Sweet's Romic alphabet (1877), and the International Phonetic Association — founded 1886 by a group of French and English language teachers led by Paul Passy — built the 1888 IPA on Sweet's system: "The original IPA alphabet was based on the Romic alphabet ... created by Henry Sweet that, in turn, was based on the Palaeotype alphabet of Alexander John Ellis."

The chain's shape is a repeated trade of descriptive completeness for teachability at each hand-off — and, tellingly, the association that produced the durable standard was founded by teachers, the people who had to use a notation at scale, not by the academic who built the fuller system. That "the usable version wins, and it's the users who ship it" pattern is the same one the vault tracks in the tactile-code standards wars: the "War of the Dots", New York Point's design, Barbier's phonetic-literacy project, and the Nemeth/UEB math-notation split. Phonetic notation and tactile notation resolve the same completeness-vs-usability tension through the same mechanism.