It is important to distinguish two use cases of phonetic algorithms:

- Recovering English spelling from English pronunciation. Soundex and Metaphone are good at this.

- Undoing the torments of Eastern-European sibilants in various transliterations of surnames, e.g. Tchaikovsky, Tschaikowski, Tchaïkovski, Ciajkovskij, Tsjaikovski, Tjajkovskij, Tsjajkovskij, Csajkovszkij, and Czajkowski. Here, Double Metaphone or Daitch–Mokotoff Soundex do a better job.

[1] https://en.wikipedia.org/wiki/Metaphone [2] https://en.wikipedia.org/wiki/Daitch%E2%80%93Mokotoff_Sounde...