I wanted to expand on the point made by @StrongBad in the comments. Even if the courses in question are not offered through the Linguistics department, any grade in a course that is closely related to the proposed graduate program will be weighted much more heavily than a random course taken for general-education or general-interest purposes.
For example, when I was on a graduate admissions committee in physics (during my grad student days), we did look at the student's performance in mathematics classes. These courses didn't carry as much weight as their performance in physics classes, but a C- in multi-variable calculus or linear algebra would be troubling. Seeing a "pass" indication in such a class would make me wonder what happened there, and would make me concerned that the student didn't really get everything out of the class that they would need for graduate studies. Even if these classes weren't required for the student's major (an applicant who had majored in chemistry, say), it would still give me pause. In effect, it's better than nothing, but not much better than that.
If I'm reading your post correctly, you're proposing to take Computer Science classes pass/fail and then apply to a program in computational linguistics. I'm not a computational linguist, but this seems like a bad idea to me. On the other hand, you might be able to get away with taking a French class pass/fail, since the skills you would be learning in that class are not as directly related to computational linguistics. (At least, they wouldn't be if your classes are anything like my college French classes were.) And if the classes are completely unrelated (a class in History or Economics, say), then it's probably fine to take those pass/fail.
On a related note: if you do decide to take these courses pass/fail, you should be absolutely sure that you can still complete the proposed minor. Many institutions (for example, mine) do not allow you to count pass/fail courses towards an academic major or minor. Check with the department in question about this, if you haven't already.