information:highlighting, linguistic:voice_change
Featural systems

Originally proposed as a category by Geoffrey Sampson (b. 1944), a featural system uses symbols representing sub-phonetic elements—e.g. those traits that can be used to distinguish between and analyse a language's phonemes, such as their voicing or place of articulation. The only prominent example of a featural system is the hangul script used to write Korean, where featural symbols are combined into letters, which are in turn joined into syllabic blocks. Many scholars, including John DeFrancis (1911–2009), reject a characterization of hangul as a featural system—with arguments including that Korean writers do not themselves think in these terms when writing—or question the viability of Sampson's category altogether.

As hangul was consciously created by literate experts, Daniels characterizes it as a "sophisticated grammatogeny " —a writing system intentionally designed for a specific purpose, as opposed to having evolved gradually over time. Other grammatogenies include shorthands developed by professionals and constructed scripts created by hobbyists and creatives, like the Tengwar script designed by J. R. R. Tolkien to write the Elven languages he also designed. Many of these feature advanced graphic designs corresponding to phonological properties. The basic unit of writing in these systems can map to anything from phonemes to words. It has been shown that even the Latin script has sub-character features.