✔ 最佳答案
If you ask me, your problem is not a communication problem. Sweet and sour sauce is typically bright red (in some occasions dark red). I suppose that duck sauce is also sweet and sour, but it is more of an orange tasting sour, whereas the red sweet and sour is more of a combination of sugar/vinegar/pineapple juice. It is possible that you are going to a crappy Chinese restaurants and they simply don't have it. Don't be surprise. Sweet and sour sauce is used more in certain Chinese cuisine, so not every regional Chinese use it. I know. Many westerners think of Chinese cuisine as a single identity, but the truth is that China is a huge country, and people eat different foods and speak in different languages. In certain aspects, it is a more diversified than United States. Some may have never used sweet and sour sauce and have no idea what you are talking about. Think of it like American BBQ sauce. The Southern vinegar based BBQ is nothing like the tomatoes BBQ sauce in the west. You can yell and scream in a California BBQ restaurant all you want, you are just not going to get the vinegar based BBQ sauce, because the waiter/waitress has no idea what you are talking about.
Here are some picture of sweet and sour sauce:
http://www.quickspice.com/scstore/images/sauce-sweet-sour_lg-7889572005.jpg
Again, I bet the Chinese restaurants you went to is just not very good, so I am not sure if giving the Chinese name to them will help, but here it goes
The Chinese characters are:
甜酸醬 (Noticed that is the same word in the first picture)
Maybe you can print out the picture, so they can see the Chinese and English names along with the exact color.
The three Chinese characters literally mean:
Sweet-Sour-Sauce.