Users of screen readers cannot read tables the same way sighted users do. Sighted users can tell at a glance what column and row a given cell is associated with, but users of screen readers need a properly coded table. Additional steps need to be taken to make tables more accessible.
Examples of tables: simple table.
The image above displays a simple table: books read by two people. Only column headers are needed to identify who read which books.
Examples of tables: complex table.
In the image above, there is a complex table: books read by two people each week. Both column and row headers are needed.
In the second example, a screen reader user will know that The Sound and the Fury was the book read by Tomiko on Week 3.
Steps to make tables accessible.
When adding tables, add a row and/or column to be used as a heading for each as appropriate. The Table Properties menu contains Headers options that allow for selecting the first row, column, or both.
Add a Caption, if necessary, to the table to inform readers of the table's content. Examples might include: Data from recent study, Table of inputs and outputs, etc.