Annotation and collaboration tools
As a linguist, you will often be working together with someone else on a document either as a co-author, or in a student-teacher relationship. Word has some easy-to-use tools to facilitate such collaborative work. I've only recently started making use of these tools myself, but I find them a very useful replacement for the scribbling-illegibly-in-the-margins method I used to use. Since comments and corrections are typed they are legible, there are no space constraints, and they can be e-mailed with the document rather than relying on transmission of paper copies. Unlike comments typed in a separate document, they can point directly at their context; and unlike comments typed directly in the body of the document, they can automatically be integrated, hidden, or removed.
The tools discussed here can be accessed from menus or from the "Reviewing" toolbar.
Comments

The Comment feature allows comments to be added to the document. In Page Layout view, recent versions of Word will display comments in "bubbles" on the right side of the text (moving text over to make room in the margin for the comment). Comments from different reviewers will appear in different colors.
Use Insert | Comment to add the comment. This opens a window at the bottom of the screen where the comment can be typed; you can edit the comment in that window or in the balloon. You can see all comments, or only comments from a particular reviewer.
Track Changes

The Track Changes tool gives you access to a simple method of keeping track of the changes a particular user makes to a document. Insertions will display in color and underlined; deletions and format changes will display in bubbles like comments.
To turn on the Track Changes mode, use Tools | Track Changes. (You can also double-click the gray TRK in the status bar at the bottom of the window to turn tracking on and off.) When the reviewer is done with the document, the writer then has the option of accepting or rejecting any change that was tracked using buttons on the reviewing toolbar.
To print comments and markup with the text, make sure that "Document showing markup" is selected in the "Print what" dropdown in the "Print" dialog.