att.ascribed provides attributes for elements representing speech or action that can be ascribed to a specific individual. [3.3.3 Quotation 8.3 Elements Unique to Spoken Texts]
Moduletei — The TEI Infrastructure
Membersatt.ascribed.directed [kinesic move pause q said sp spGrp stage u vocal writing] annotationBlock change incident setting shift
whoindicates the person, or group of people, to whom the element content is ascribed.
Status Optional
Datatype 1–∞ occurrences of teidata.pointer separated by whitespace

In the following example from Hamlet, speeches (sp) in the body of the play are linked to castItem elements in the castList using the who attribute.

<castItem type="role">
 <role xml:id="Barnardo">Bernardo</role>
<castItem type="role">
 <role xml:id="Francisco">Francisco</role>
 <roleDesc>a soldier</roleDesc>
<!-- ... -->
<sp who="#Barnardo">
 <l n="1">Who's there?</l>
<sp who="#Francisco">
 <l n="2">Nay, answer me: stand, and unfold yourself.</l>

For transcribed speech, this will typically identify a participant or participant group; in other contexts, it will point to any identified person element.