The reconstructed active imperfect is يَقْوُلُ. The vowel of moving wāw is transferred to the preceding vowelless qāf, producing يَقُولُ. This is vowel transfer (naql al-ḥarakah).
Word / formMeaning / explanation
يَقُولُhe says.
يَقُولُونَthey (men) say.
يَقُلْنَthey (women) say.
In the feminine plural, the consonant-cluster situation with the nūn ending also removes the middle wāw; this is an additional operation beyond simple vowel transfer.