tekz999 is soooo right. Dont treat her like she is Japanese.
#1, you dont know how Japanese treat each other. If you were to go to Japan, and your host family were to take you to Denny's, you too would be disappointed. It is impressive to see such a young girl go overseas to learn English. One of my best suggestions is NOT to speak ANY Japanese. BUT learn just a few to show that you too are trying to communicate with her.
if you need to know some phrases, let me know. Some of the Japanese books are oh so wrong.
Here is a site that can help you translate words in emergencies:
http://www.alc.co.jp
You can either type japanese or english characters.
While riding the subways, I still see many Japanese reading English newspapers or using the FRIGGING pocket translators, but their English is still crap! for a Japanese student so young as 13, this is a GREAT opportunity for her. If you are to give her a hardcourse in the English-speaking culture, she may cry, but she will benefit a lot from this. She really really needs this. Oh yea, expect the crying a lot. Dont sympathize with her. Such kick in the arse is quite a norm here for learning something that they are unfamiliar with.
I have spent about 10 years living in Japan and what a change i have seen. From time to time, i teach English pt to Japanese students. and as any 13-year old, they too (Japanese) tend to distant themselves. As your student exchange may not want to TRYYYYY to speak English, just talk to her and ask her many questions.
AND TRY NOT TO SPEAK SLOWLY... speak as you would but clearly. Once she goes back to Japan and learns those words when she studies, she will always remember the time she spent with you. And I am sure that she may want to visit you again or even invite you to Japan. As an island, they are quite isolated from the rest of the world so any connection beyond their seas is a great one.
so here is the list of what to do and NOT do (my suggestions):
DO:
talk to her
ask her questions
speak slowly
take her to YOUR favorite places to go and eat (Korean, Chinese foods are favorite)
give her forks and spoons (not chopsticks)
help her with English words
encourage her to speak and ask questions
give her food from your fridge. It is EXTREMELY rude for her to go to your fridge and serve herself though you offer. coax her into doing this gradually.
let her roam the shopping mall on her own, but standby closely in case.
wake up with her early in the morning about 6am (they generally wake up everyday of the week to attend classes)
as MUCH of your culture that you can give her.
AND DO take her to the grocery store. Bell peppers, cucumbers, potatoes, etc are very small here in Japan. To compare such vegetables may seem boring, but for someone who is adapted to seeing small vegetables and seeing larger ones overseas is an amazing event! Walmart is also a great place!
do NOT, I repeat,
DO NOT
give her sympathy when she becomes frustrated (will make it worse)
give her chopsticks
give her anything Japanese (food, toys, clothing, nothing)
talk too much. Japanese always listen but hardly have a chance to practice their English.
DO NOT give her raw fish. raw fish are different. If you simply cut up a salmon and serve it to her, she could get sick. Again, just let her eat what you usually eat.
(you can ask me more if you need)
She IS A HOST of her country. You ARE A HOST of your country. The purpose of this exchange is to bring both cultural aspects home.
What she learns from you will be given to others here in Japan. They usually speak very highly of their host families but they are also very honest and upfront. so if you pick your nose, they will say it.
Hope that helps. let me know if you have more in-depth questions.