נחמיה ג:יז פירוש: רש״י

half the district From that bailiwick, the half district, he built this structure. In the word לְפִּלְכּוֹ, the “kaff” has a “dagesh,” as one says from מֶלֶךְ, מַלְכּוֹ, from עֶבֶד, עַבְדוֹ, so does one say from פֶּלֶךְ, פִּלְכּוֹ, for [if] the last letter of the noun is one of the letters “beth,” “gimmel,” “daleth,” “kaff,” “pey,” or “tav,” it is punctuated with a “dagesh.”