Appendix:German cognates with English/Regular cognates with differing consonant values/Proto-Germanic Fricative Consonants

Proto-Germanic *h
The correspondences for *h are somewhat complicated as English exhibits two kinds of changes from *h. In English, *h can become a gh /∅/, or it can become gh /f/. This yields two possible rules of correspondence.

Proto-Germanic *s
Both languages exhibit some tendency to rhotacization.

German d ~ English th
We treat alternations between voiced and unvoiced th as equivalent.