I found this information from a video blog about differences between Chinese and Indian songs (that video blog was by ShenLimTV, you should check out his YouTube account!). It was said that when it comes to, for example, love songs, there is slight difference of its theme depending on what culture the songs are from. 

The owner of the video blog compared the theme of love brought by Chinese, Korean, and Japanese songs. According to him, Chinese love songs are usually about showing how much you love/cherish someone, while Korean love songs are more about wanting your loved ones to come back to you after getting separated. On the other hand, Japanese songs are about appreciating the time you've spent with your loved ones by thanking them. 

I listen to a lot of Japanese songs, and a few Korean songs too. But had never realized on this slight difference between their themes until this video blogger stated so! Since I'm a fan of Japanese rock music and VOCALOID, I could only tell that Japanese really love telling stories and conveying them in a song. If you're interested, try out "LOST" by The GazettE, or "WORLD's END UMBRELLA" by Hatsune Miku! You could tell that there's a storyline built throughout the lyrics.

What about music from other cultures, though? I don't have other songs than Japanese songs, so I'm really curious the theme of music from other cultures has any difference!