Here the middle radical carries a kasrah: يَفْعِلُ. The prefixes and endings follow the same 14-slot arrangement.
Person
Gender
Singular
Dual
Plural
Third person
Masculine
يَفْعِلُ
يَفْعِلَانِ
يَفْعِلُونَ
Third person
Feminine
تَفْعِلُ
تَفْعِلَانِ
يَفْعِلْنَ
Second person
Masculine
تَفْعِلُ
تَفْعِلَانِ
تَفْعِلُونَ
Second person
Feminine
تَفْعِلِينَ
تَفْعِلَانِ
تَفْعِلْنَ
First person
Masculine/Feminine
أَفْعِلُ
—
نَفْعِلُ
Compare يَفْعَلُ and يَفْعِلُ: the person/number framework stays the same, while the vowel on the middle radical changes.