He studied Italian.

1. He studied a course on Italian.

2. He studied a course in Italian.

Which is the correct one? I think it would be fine to say studied a course on Italian/French If you went to a school and studied an Italian or French language course.

A native speaker might think otherwise.
Your comments are welcome.
I'd say "he took a course in Italian"

In your examples, I'd use "in", or "an Italian course".
Well, first: we don't study a course, we take a course; we study Italian.

I took a course in Italian.-- this is the one that seems natural to me: Italian is the subject title.
I took a course on the evolution of the endoproct tentacular system. -- this explains the topic of the course rather than naming it.

Others may have different opinions.
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I'm glad you agree with me, MM Emotion: smile (long time no see - my fault!)
This durn time lag-- I didn't even see your post squeeze in there when I finally posted.
Oh no! I just wanted to state the fact that I know I've been scarce of late, and that I was glad that we think in the same direction!

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