Have you selected dictionary in the Spell check settings (menu settings or Ctrl+F7)? When you activate spell check, e.g. from the View menu, you should see wait screen that dictionary is loading.
If you have any syntax highlighted, in thei case PSpad checks comment, strings and other elements what can contains "text", not a code. -- <https://forum.pspad.com/read.php?2,75507,75514> PSPad freeware editor https://www.pspad.com