BASES

INDICATE ESSENTIAL MEANING OF WORD 

        SOMETIMES NOMINAL:          ART‑ 

        SOMETIMES ADJECTIVAL:    FORT‑ 

        SOMETIMES VERBAL:             DUC‑, DUCT‑

CAN FORM WORDS BY THEMSELVES 

        VERB             FORT             FIRM

CAN ADD A SILENT "E" 

        GRAV(E)       FIN(E)            CED(E)

CAN HAVE DIFFERENT FORMS 

        GRAV‑           LATIN            GRAVE 

        [GRIEV‑]       FRENCH       GRIEVE

Note: "grave" and "grieve" are called doublets because they are spelled differently but come from the same source word, namely (Latin GRAV-).