Japanese VS. Mandarin Chinese
Im sorry if I am incorrect about this, but I have been told that Mandarin Chinese is strongly dependent on tone to get a point across. Like you could say the same exact thing but in two different tones and they would mean different things. If this is the case for Mandarin Chinese, is Japanese somewhat like that as well? I'm sorry if I am being uneducated and getting this completely wrong.
Japanese is not a tonal language, but apparently it has a "pitch accent": https://en.wikipedia.org/wiki/Japanese_pitch_accent
My high school English teacher would call that "putting the em-PHA-sis on the wrong syl-LAB-le."
Thankfully, pitch accent isn't super necessary. You'll most likely still be understood even if you get the pitch-accent wrong, which is why most textbooks don't teach it and there isn't any way of showing it in romaji.
Some words in Japanese exist with different meanings depending on if you use the pitch on the first or second mora. Japanese has many homophones. But also kana and kanji don't represent the pitch. However, if you know the word you can see the difference in written Japanese because different kanji are used.
While yes there is little similarity, it would be wrong to say no similarity due to Japanese Kanji coming from China, as well as around 60% of it's vocabulary being Sinitic. The reverse also happened with many Chinese characters coming from modified Japanese kanji, along with the implied onyomi pronunciation sometimes.
I am Chinese and I speak it too. I also learned and heard some Japanese (mainly from anime haha). I have to say that some Japanese can sound like chinese then at the same time it doesn't. But the kanji looks like chinese and means the same thing just sounds differently. So basically some would sound like chinese, not exactly, but similarly and not all Japanese words would sound somewhat like Chinese.
Most Mandarin Chinese has a lot of the words that sounds the same but means different things but not all of them sound the same. Japanese has katakana which sounds exactly like hiragana (and maybe with some extra sounds in there too) but it is used differently. So katakana and hiragana Japanese may sound the same but depending on what you're talking about it is easy to know what to use (if you learned Japanese).
Sorry if I went off topic and if this is long haha. (I may be wrong on some stuff but these are all from my experiences and knowledge)
Chinese does rely on intonation, and even then multiple words can have the same reading and same intonation, and some words even have multiple readings/intonations. So yeah, the tone is part of the word. Japanese doesn't really have specific intonations, but it's like English, where you have a certain emphasis on certain words.
Japanese doesn't have tones like Mandarin and the other Chinese languages do, which is why there are so many homophones in modern Japanese -- they borrowed them from China 1300 years ago, and adapted them to Japanese phonology, but didn't borrow the tonal parts.
So often in Japanese there are words that sound exactly the same and mean different things. 市街 means city streets, but 市外 means outside the city! And 死骸 means a dead body! But all three are pronounced shigai. You will meet more and more of these words as your Japanese advances.