Modifying the Teacher role is a bad idea for several reasons.
The permissions of a role can only be used within the context
in which the role is assigned. Teacher is normally assigned in a Course context. Having the ability to create courses in a Course context is completely useless, since Courses can only be created in categories, and Catgory is a higher level context.
An alternative is to assign your modified Teacher role at the Category level. Also a bad idea. Do you really want users with this role to be Teachers in every course within the Category? No, you just want them to be be Teachers within the courses they create.
An even worse alternative would be to assign the modified Teacher role in the System context. Then your Teachers will Teach every course, including the Front page.
Convinced that modifying Teacher is a bad idea? Then your first step should be to do a "Reset to defaults" on the Teacher role.
The correct solution is to assign the Course creator role to users in the appropriate category.
- As admin, click Site administration -> Courses -> Add/Edit courses.
- On that page, click the appropriate category link (if you only have one category, it is probably called Miscellaneous).
- On the next page, click the Assign roles link in the upper right corner of the page.
- On the next page, click Course creator.
- On the next page, select one or more users that you want to assign to this role and assign them using the arrow button.
It doesn't matter if the users you assign Course creator to also have role assignments in other contexts. For example, some of them may also be Teachers in certain courses and some may not.