You can check the spelling of a text layer in your project via the Text editor.
Use the spelling checker in the Text editor
In the Format pane of the Text Inspector, do one of the following:
Click in the Text editor, then choose Edit > Spelling and Grammar and choose an option from the submenu.
Control-click in the Text editor, then choose an item from the shortcut menu.
When a spelling error is found, the text is highlighted in the Text editor. If the Text tool is active when the spelling is checked, the text is also selected in the Canvas.