343. The sound changes in the perfect middle system are shown in the paradigms below (§ 345).
344. a. In the perfect middle of πέμπω (πεμπ-, send) πέπεμ-μαι is written, since -μμμ- can hardly be pronounced otherwise than as -μμ-. So πεπέμ-μεθα, πεπεμ-μένος.
b. ἐλέγχω (ἐλεγχ-, test) makes ἐλήλεγ-μαι, ἐληλεγ-μένος (dropping one -γ- from -γγ-μ-), but ἐλήλεγξαι, etc.
c. Older writers have in the perfect and pluperfect indicative middle 3rd plural a few forms in -αται, -ατο, before which a π- or κ- mute is aspirated.
345. Perfect Middle System