The story
- Proto-Indo-European*né
- Proto-Indo-European*n̥-
- Proto-Germanic*un-
- Proto-West Germanic*un-
- Old Englishun-
- Middle Englishun-
- Englishun-
- Proto-Indo-European*per-der.?
- Proto-Indo-European*pér
- Proto-Indo-European*pró
- Proto-Indo-European*pro-
- Proto-Italic*pro-
- Latinprō-
- Latinnūntius
- Latinnūntiō
- Latinprōnūntiō
- Old Frenchprononcier
- Middle Englishpronouncen
- Englishpronounce
- Englishpronounceable
- English todayunpronounceable
From un- + pronounceable.
Etymology from Wiktionary, CC BY-SA 4.0.