Grading term papers and reports written by non-native speakers
Grade everyone the same on things like word choice and sentence structure, but make that portion of the grade a small part of the overall grade for the paper.  (If you are in the United States, you will find students who are the product of U.S. high schools with limited vocabulary and no idea of sentence structure.)

Edit: If you don't grade everyone on the same scale, you will inevitably get complaints.  I'd argue that what is important (for learning) to students in your class is the formative feedback on their writing, not the specific number of points.  If the dean complains, 'splain that you teach computer science.

{Time passes} As Damian has said in the comments, you will need a grading rubric that assigns relatively low points to word choice and sentence structure, more points to overall organization, still more points to quality of research, etc.  Then you'll need to show how the overall grade was computed, using the rubric.  To repeat myself, the formative comments you make, particularly on word choice, sentence structure, etc. will be more important to learning than the actual points.