if I recall correctly, SilkTest uses the actual text of what it "thinks" is the label for the TextField. By "think" I mean for a TextField the label should be to the left of the TextField if standard UI prqctices are being followed.
Silk will always apply a name to each object it sees. As a default for a truely unlabeled object it'll use a variant of the objects' class name.
While it has changed slightly over the years, Silk has always used a left to right, top to bottom association to determine what it will call each object it encounters. As you've probably noticed, the results of this simple algorithm are not always perfect.
The quickest way for you to determine which declared name applies to which object is to compile the output of a Record/Window Declarations operation, then open Record/Window Identifiers and point your mouse cursor at each object.
the text wouldn't have to be to the left; could be above the control.
it would be extremely unlikely that a developer would want to create a text field with no label to the left or above it -- the user wouldn't know what to do with the control.
per Segue user's guide: the caption tag is "The caption or label as it appears to the user." the prior text tag is "Closest static text above or to the left of the object. Prior text tags begin with the ^ character."
Silk test when identifying "Captions" always searches for what Segue calls qualifier text. The text can be placed to the right, left, above or below the control.
However in some apps that we have tested we had a funny observation. When we recorded the window delclarations some of the controls e.g. textfields did not have the logical identifiers that should have been the case i.e, the caption of the textfields was not the static text that was closest to the control. Instead it was the name of the Frame that enclosed the control. And sometimes it was the pagelist name to which the control belonged.
This way we concluded that for Silk to accept the static text as the qualifier text, the static text has to be in some permissible limits of the control. (someone said it was fixed in pixels, debatable however ...)
In total absence of the qualifier text, it then accepts either the name of the frame if any or the page that encloses the control. If all these are absent then Silk refers to these objects by the control tag or Index.