What's the nuance between these two example sentrences from Genki I?

Question

I'm currently studying Japanese using Genki as one of my resources. At the end of Lesson 8 for the second edition of Genki I, in a section called Expression Notes 9, the textbooks tries to explain that as many irregular verbs are just the combination of a noun and する, many of the nouns can be used as the object of a sentence.

They then go on to give two examples of this, the first set being the two sentences:

私は日本語の勉強をしました。

vs

私は日本語を勉強しました。

But I'm not sure I understand the nuance between these two sentences. If asked to translate the sentiment, I would've come up with the second sentence more easily, I think. Is there a slight difference between these, or is it just another way of expressing the same concept? And if so, does anyone have any more examples or recommendations on additional resources covering this topic? Thanks!

Answer 1

の marks a word modifying the word after it. In AのB, A modifies B. In the first example, 日本語 is modifying 勉強. When you write 日本語の勉強, you are essentially saying "Study of Japanese" or "Japanese study". "Japanese Study" is the object of する. The literal translation of your first example would be:

私は日本語の勉強をしました。
I did Japanese Studies.

The second one is more straightforward. 日本語 is the object of 勉強する. 勉強する essentially acts as a verb.

私は日本語を勉強しました。
I studied Japanese.