Answer: Yes; you do! This is known as "paraphrasing" ; and you should always properly cite your source(s) used when doing so.
Even when you use some quotations from any original source(s) when you paragraph, you need to put the actual words — even "two-word phrases" — in quotation marks (and be sure the original source is given credit.
In fact, failure to PROPERLY paraphrase and cite sources used is, unfortunately, common — and is known as "accidental plagiarism" — but nonetheless is still "plagiarism" — and still has consequences; including lower grade on the assignment; having to "re-do" the assignment, having to write another assignment, referral to the dean for notation on disciplinary record; a failing grade on the paper, a failing grade in the course; attendance at an "ethics" seminar.
A one-time offense of "accidental plagiarism" might be given more leniency (in the academic realm) if it determined that is a "first-offense" and truly "accidental" ; however, why not do things right all-around?
Furthermore, properly citing source(s)—and properly quoting and citing paraphrased text—including "two-word phrases" — if done properly and in conjugation with a well-researched and organized paper with credible sources used and correctly cited formatting — tends to demonstrate credibility.