Yaktubu has an understood huwa; taktubu can imply hiya or anta depending on context; aktubu implies anā; naktubu implies naḥnu.
Context matters for taktubu: «فَاطِمَةُ تَكْتُبُ» implies hiya, whereas «تَكْتُبُ يَا خَالِدُ» addresses anta.
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The person marker and the concealed subject
Pronouns: definitions, forms, usage, and parsing
Yaktubu has an understood huwa; taktubu can imply hiya or anta depending on context; aktubu implies anā; naktubu implies naḥnu.
Context matters for taktubu: «فَاطِمَةُ تَكْتُبُ» implies hiya, whereas «تَكْتُبُ يَا خَالِدُ» addresses anta.