When you use it
Reach for this when you must split a word into its morphemes or say whether a suffix is an እርባታ (inflectional) or ምስረታ (derivational) affix.
Watch out
Do not call a suffix derivational just because it is added. Check whether the word class changes: ፍየል plus -ኦች stays a noun, so it is inflectional, while ባህል plus -ኣዊ becomes an adjective, so it is derivational.
Drafted from Grade 11 Amharic, pages 54-73, then checked twice before it went up

