Someone asked me a tough question about the translation of the Japanese 'ya' and 'to' :( I think many times it is difficult to translate them easily with simple grammar.
Here are some examples that I will write in English and then put the translations at the bottom.
1. I like Dusty and Kuro. = both
2. You can buy bagels and small cakes at Tsukuba Bagel. = both
3. I can play tennis and badminton. = both (but not at the same time!)
4. Let's eat spaghetti and salad for dinner. = both
5. I went to Ueno, Ginza and Shibuya. = all 3 places, only these places
6. Please catch Dusty and Kuro. = both
7. Please catch Dusty or Kuro. = 1 of them, either is ok
8. Please catch either Dusty or Kuro. = 1 of them, either is okay, nuance is there are also other cats here
9. I will buy bagels or sandwiches for lunch. = only 1, either is ok
10. Do you want spaghetti or pizza for dinner? = only 1, either is ok
11. I want spaghetti and pizza. = both
12. I want both spaghetti and pizza. = both (stronger feeling)
13. Sorry, you can have either spaghetti or pizza. = only 1, (stronger feeling)
14. I went to Ueno, Ginaza, Shibuya, etc. = 3 places plus other places
1. I like Dusty and Kuro. = both
ダスティとクロが好きです。
2. You can buy bagels and small cakes at Tsukuba Bagel. = both
つくばベーグルでは、ベーグルと小さなケーキが買えます。
3. I can play tennis and badminton. = both (but not at the same time!)
私はテニスとバトミントンができます。
私はテニスやバトミントンができます。
4. Let's eat spaghetti and salad for dinner. = both
夕食にはスパゲッティとサラダを食べましょう。
5. I went to Ueno, Ginza and Shibuya. = all 3 places, only these places
上野と銀座と渋谷に行きました。
6. Please catch Dusty and Kuro. = both
ダスティとクロを捕まえてください。
7. Please catch Dusty or Kuro. = 1 of them, either is ok
ダスティかクロを捕まえてください。
8. Please catch either Dusty or Kuro. = 1 of them, either is okay, nuance is there are also other cats here
ダスティかクロを捕まえてください。
9. I will buy bagels or sandwiches for lunch. = only 1, either is ok
昼食にはベーグルかサンドイッチを買います。
10. Do you want spaghetti or pizza for dinner? = only 1, either is ok
夕食はスパゲッティもしくはピザどちらにしますか。
11. I want spaghetti and pizza. = both
スパゲッティとピザが食べたい。
12. I want both spaghetti and pizza. = both (stronger feeling)
スパゲッティとピザの両方が食べたい。
13. Sorry, you can have either spaghetti or pizza. = only 1, (stronger feeling)
すみませんが、スパゲッティかピザどちらか食べれます。
14. I went to Ueno, Ginaza, Shibuya, etc. = 3 places plus other places
上野と銀座と渋谷に行きました。
15. Do you use refill packs for your household cleaners and toiletries?
家庭用洗剤と洗面用洗剤の詰め替えパックを使いますか?
家庭用洗剤や洗面用洗剤の詰め替えパックを使いますか?
In Japanese "to" is clearly a limit of ONLY those things. "ya" means those things plus other things. So "ya" is the same as "etcetera" in English :) Sometimes we use etc or another word if we really want to show there are more choices, but most of the time it is not necessary.
3. I can play tennis and badminton. =
私はテニスとバトミントンができます。
私はテニスやバトミントンができます。
Maybe I can play other sports, too, but I am focusing on tennis and badminton. If other sports are important, I can say:
I can play tennis, badminton, etc.
I can play tennis, badminton and some other sports.
Would you like tea and coffee? = both (this is strange English)
Would you like tea or coffee? = only 1
Would you like tea, coffee or something else to drink? = tea is ok, coffee is ok, a different thing is ok
"ya" is really difficult :( I don't like it in Japanese so I never use it. I only use "to", "ka", "nado", "nanika"
You should read this Japanese page and study kokugo :) Then you will agree with me that English is MUCH easier!