The main language spoken here is Mandarin, and people generally do not really understand English. There are slight cultural differences between Mainland Mandarin Chinese and Taiwanese Mandarin. The elders of Taiwan also speak a language called Taiwanese Hokkien, which is another one of the national languages of Taiwan. Hokkien and Mandarin sound very different from each other!
New Taiwan Dollars (NTD, 新臺幣) are used here in Taiwan! Taiwan uses both cards and cash, but for smaller stores, cash is a safer option because not all of them have a card reader! It is always safe to have at least 1000 NTD on you, which converts to $31.34 USD.
A bottle of water roughly costs around 20-30 NTD, which is under $1 USD!
The best meal I had this week was probably at the restaurant ShuangYue (Double Moon) near Da'An district. It has a Michelin Bib Gourmand award for its famous chicken and oyster soup, which they steam to bring out all the goodness. The broth comes out extremely fresh and full of flavor, and the meal is very cheap. Just be aware that around dinner time, there's usually a long line!