Learn French: Il a dit que ce jour-là, il était malade. - He said that on that day, he was sick.

When reporting speech in the past, time markers have to shift to match the perspective. The original speaker likely said "I am sick today" (aujourd'hui). Because we are reporting this in the past (Il a dit que...), "today" changes to "that day" (ce jour-là).

Why is the second verb était in the imperfect tense here?

This demonstrates the French sequence of tenses (concordance des temps). Since the introductory verb a dit is in a past tense, the reported speech must shift back in time. A present tense statement like "Je suis malade" shifts to the imperfect (était) to describe that ongoing past state.

What purpose does the -là serve on ce jour-là?

The suffix -là emphasizes distance in time or space, meaning "that" instead of "this." While ce jour can just mean "this day," adding -là clarifies that we are talking about that specific day in the past, contrasting it with the present moment.

Could the second il refer to a different person than the first il?

Yes! Just like in English, "He said that he was sick" could mean he was talking about himself, or he was talking about a third person (like a friend). You have to rely entirely on context to know which "he" is which.