«جِدِّي جَهْدِي»
“My earnestness is my effort.”
When the difference occurs near the start of a word, the shared structure is still readily heard. A medial addition preserves sounds on either side; a final addition modifies the ending while retaining much of the overall resemblance.
Classification requires more than saying that one form is longer: the position of the difference matters as well. An effective method is to write both expressions separately and identify their common and extra letters.