Chinese is very hard to learn.
However, when learning Chinese you'll probably learn either Standard Mandarin or Hong Kong Cantonese.
Here are the reasons that it's a hard language to learn:
- Both languages are tonal. This means that one pronunciation in pinyin or Jyutping (English-written Chinese) is different from another. Let's say (for example) that you have "jie". One "Jie" means Clean/pure and another "jie" means Sister. If you hear the Chinese language spoken, both Mandarin and Cantonese you will notice have lots of ups and downs in their Words.
- Chinese does not have an alphabet. When learning writing, you will learn radicals (parts of characters) and their characters. There's no ABC in Chinese, there's just water, mouth, heart, small, etc. Putting them together creates the Words. There are also two different writing systems, traditional and simplified. In most of mainland China, simplified is used, but in Taiwan and Hong Kong, traditional is used.
Cantonese is harder than Mandarin, I think, because Cantonese has 6-9 tones (ups and downs) while Mandarin only has 6.
Mandarin is softer, and Cantonese has more G and B sounds.