Labeled include Buttons, Cells, and Label.
Labeled can have mnemonic, in which case the underline should be stripped from the text returned to accessibility , and Labeled can have a graphics (such as an image), the Labeled can show either the text and the graphics or both.

Buttons and Label use TITLE from Labeled (implemented in LabeledSkinBase) which handle mnemonic properly but ignore the graphics.
Cells have their own implementation of TITLE, ignoring mnemonic (which is okay, as mnemonic parsing is false for Cells). The only Cell that handles graphics properly is ListCell.

Ideally TITLE could be handled in LabeledSkinBase for all subclasses for Label.

Note, currently this code fails
Button button1 = new Button();
button1.setGraphic(new Text("Click me"));
That 'Click me' is not picked up by the screenreader.