I'm learning Mandarin, in China, and it is extremely difficult.
Chinese, unlike Japanese, has no alphabet. It's all unique characters for each and every word, or a combination of several to form a whole idea or concept.
Chinese (Mandarin) also has tones, 4 to be exact, and it's a tricky process to begin using and learning tones as a form of communication when, as English speakers, we don't have tones. We do, but they're natural tones that are not taught. In Chinese, you can't mess around with the tones. If a word is 3rd tone, then it's 3rd tone.
If I take one Chinese word, let's say 'qing', this doesn't mean anything unless it's in context or with the character of whatever idea you want to express.
Saying 'Qing' in the first tone could mean several things like dragonfly, rest-room or distinct.
2nd - strong, clear/fine (weather).
3rd - to ask, room.
4th - celebrate, exhausted.
All of these separate words would each have their own unique character in order to express it in writing. Chinese doesn't have many differeny sounding syllables compared to English. Only a few hundred while, in English, we have thousands and thousands.
The grammar of Chinese though, is extremely easy. Much more simple than English as there is no tense.
For example, 'le' is used at the end of a sentence to say that something is happening now.
I'm going to town le. This would mean right now, at this moment. Whilst 'I'm going to town' could mean any time in the future. You just need to be specific. If you put 'le' after a verb, it indicates past tense.
I speak to you.
I speak le (spoke) to you.
Future tense would be expressed using time. Tomorrow, I speak to you. In 2 minutes I speak to you, etc etc.
Obviously, China has three main dialects and the speaking is all entirely different. Cantonese, Shanghainese and Mandarin. As well as many many others.
Mainland Chinese uses simplified characters while Hong Kong, Singapore and Taiwan use Traditional characters. As a whole, the difference isn't huge, but traditional characters are a hell of a lot more difficult to learn. But, nonetheless, they're both pretty damn tricky.
So, if you want to learn Chinese, you have a lot of work ahead of you. There are a lot of concepts you'll need to get over in your mind to be able to understand how it all works exactly.
Japanese is the same, but it has an alphabet as well as individual characters. But if you don't know a Japanese character you can write it in their alphabet or someone can write it in their alphabet for you, then you will be able to read it.
Japanese has two alphabets. Hiragana and Katakana, each being 46 sets of totally unique syllables, not letters.
I hope this was of some help to you.