The story
- Proto-Indo-European*úp
- Proto-Indo-European*upér
- Proto-Germanic*uber
- Old Englishofer-
- Middle Englishover-
- Englishover-
- Middle Englishespecial
- Englishspecial
- Englishspecialize
- English todayoverspecialize
From over- + specialize.
Etymology from Wiktionary, CC BY-SA 4.0.