⟨dd⟩

⟨dd⟩ is an English consonant digraph consisting of double D.

In English, it is typically the result of consonant doubling, e.g. plod can be inflected to plodded, plodder, plodding, etc. This reliably represents a voiced alveolar stop /d/ sound that follows a short vowel. It is always at the end of syllables (coda position).

It's also found in add and odd for the three letter rule. And in some names, e.g. Judd.

However, in Welsh, dd represents a voiced dental fricative /ð/ sound, and this is often found in personal names (e.g. Bleddyn /ˈbleðɪn/ Dafydd /ˈdævɪð/) and place names (e.g. Gwynedd /ˈgwɪ.neð/, Pontypridd /ˌpɒn.tɪˈpri:ð/), and the name of the national cultural event, the Eisteddfod. This can appear at the start of syllables (onset position), or at the end.