How to search for "this box" but not "in this box"

I’m looking for the proper search syntax to find the string “old language” but not the string " Lessons in the old language" in a restricted set of my database. “Lessons in the old language” appears in the header of one or more documents, so it shows up on every page. This is no help. I want to either exclude the header itself of the pdf, or some way to exclude this repetitious phrase in the header so that the search command finds only what is in the body of the pdf.
Any suggestions? Apologies if this has already been answered.
Thank you,
John Robert

It’s not exactly the same but you could try "old language" but NOT AFTER "in"

Thank you. That helps. Now I would like to add the condition Not AFTER “lessons” as in “lessons-old-language”. The “lessons-old-language” is part of a URL that repeats in a header, like “Lessons in the old language” that I mentioned in my original post.
So I want to search for “old language” but not after “in” and not after “lessons”
So would that be phrased like the following: “old language” but NOT AFTER “in” AND NOT AFTER “lessons”

These kinds of things are covered in the Appendix > Search Operators section of the help and manual.

Hello Bluefrog,
Yes, I know about the search operators in the Appendix, but I didn’t find what I was looking for there, or didn’t understand how it was explained. More examples there would be helpful.
Regarding my second post above, that issue has been solved. I used “old language” but NOT AFTER “lessons” and it took care of both of them, because the word “in” also occurred just before “old language” on those occasions where “lessons” occurred before “old language”. My luck that one NOT AFTER was enough for both situations.