Common mistakes
The middle radical is و or ي. It stretches into a long vowel: قَالَ: and shortens before a consonant ending and in the jussive: قُلْتُ, لَمْ يَقُلْ.
زَيَدَ → زَادَ Past: heزَيَدَتْ → زَادَتْ Past: sheزَيَدْتَ → زِدْتَ Past: you (m.)زَيَدْتُ → زِدْتُ Past: I