diacritical

The story

1. Proto-Indo-European*dwóh₁
2. Proto-Indo-European*trísinflu.
3. Proto-Indo-European*dwís
4. Ancient Greekδιά (diá)
5. Ancient Greekδια- (dia-)
6. Proto-Indo-European*krey-
7. Proto-Indo-European*krinyéti
8. Proto-Hellenic*kríňňō
9. Ancient Greekκρῑ́νω (krī́nō)
10. Ancient Greekκρῐ- (krĭ-)
11. Ancient Greekκρῐτής (krĭtḗs)
12. Ancient Greekκριτικός (kritikós)
13. Ancient Greekδῐᾰκρῐτῐκός (dĭăkrĭtĭkós)
14. Englishdiacritic
15. Proto-Indo-European*h₂el-
16. Proto-Indo-European*h₂élisder.?
17. English todaydiacritical

From diacritic + -al.