The masculine third-person singular is قَالَ, but the first-person singular is قُلْتُ and feminine third-person plural is قُلْنَ. Adding endings changes the syllable structure; retaining the long alif would produce an impermissible consonantal meeting.
Word / formMeaning / explanation
قَالَhe said.
قُلْتُI said.
قُلْنَthey (women) said.
The form “قَالْتُ” is not the proper conjugation. قِلْتُ is passive, not the active perfect.