I'm wondering what a "T" on an assignment that has not been graded indicates as I have not seen this before
It indicates that the assignment has been turned in as a Text Entry assignment rather than a file upload, link, or media recording. Here is a Guide with the various icon types and their meanings: How do I use the icons and colors in the Gradebook?
Hi Darlene and welcome to the Community! The "T" means that for the assignment a text entry was submitted by the student. If you go to the SpeedGrader you should be able to see this submission. Text entry is where the student actually typed in the assignment in Canvas as opposed to uploading a document.
I hope this helps and best wishes!
Retrieving data ...