Contributing here for completeness. I have translated Deligne's original paper into English (it is only 35 pages) - https://drive.google.com/file/d/1wxVbCrm_0D4jInvG1pd1vhnI7YnvSk0S/view?usp=sharing Still, I suggest to first get acquainted with the theory of etale cohomology and the exposition of the proof in Milne and only then turn to the original paper to fill in the details.
Added: I have found certain typos but they are not crucial for the exposition.