why do some students study abroad?

I would say that there are a number of reasons. The following seem to me to be some of the most valid and common:

1. Desire to diversify. Most people grow up in one country, spending 17, 18, or 19 years of their life among the same people with the same culture. Studying abroad allows you to place yourself in something completely different, inherently foreign. I think it helps a lot of people to be able to better understand themselves and their own native culture by being at once part of and simultaneously outsiders looking in on a foreign culture.

2. Learning from the place. Related to the above is what you can learn from the place. Learning foreign language represents a challenge to most people. Living abroad in a nation where your mother tongue is not used allows you to immerse yourself in that language. Even if your classes are conducted in your native language, every time you want to take a taxi, buy a snack, or say hello to a person to whom you are attracted, you are forced to use (and further) those skills.

3. Cost of education. Education is often quite expensive. For residents of the United States, for instance, the cost of attending an elite institution of higher learning can simply be outside of their ability to pay. Excellent foreign universities can often be attended at the same or lower cost than their domestic counterparts. The best Canadian schools, for instance, typically cost much less than schools in the Ivy League.

4. Course/degree offerings. Often students want to pursue studies that they simply cannot undertake in their home country as such courses/degrees are not offered, or are highly limited. In large countries like the United States, students can find institutions that offer degrees in just about anything, but this is often not the case in many smaller countries.

5. Doing research. Certain countries offer greater opportunities for research than others. If you wanted to do cutting edge stem cell research, for instance, the United States probably would not be the best place to conduct your research. It might make sense to go to another country where you could do that work to earn your PhD.

6. Quality of education. Certain institutions have tremendous prestige and cache. Their degrees are considered valuable around the world. Try searching for a list of current world leaders who have degrees from Oxford, Cambridge, Harvard, and Yale. Its almost a challenge to find a president, prime minster, or premier who has not attended one of these institutions.

I studied abroad mainly because it was a requirement for my major (Spanish), but I don't regret it and would definitely do it again. Studying in a country with a different language than yours is a great way to learn the language. But even if you go to a country with the same language as your own, you get the chance to experience a different culture and different traditions. It gives you the opportunity to step out of your comfort zone and really become a more well-rounded person.

Why do I suspect that a birther is calling this question? Hawaii is aspect of the United States. Therefore, you could no longer be learning overseas and don't have to study Japanese (or Arabic).