016. Chapter 2.2.B
Segolate nouns follow a different pattern in the singular, but are regular in the plural.
Hebrew, Noun Morphology, Gender and NumberSegolate Nouns, Spelling Changes
Bible Study; Lecture; Sermon Prep
Future Seminarians; Ministers
Bartelt, Andrew, "016. Chapter 2.2.B" (2007). Elementary Hebrew. 16.