Actually I am not really focusing which tone a Vietnamese or Cantonese word has. Although I can speak Mandarin Chinese at a decent level, I can’t read some difficult characters.
Knowing the etymology of a word, can also make it easier to remember a word.
For example: the word for black in Turkish: kara, Japanese 黒 (Kuro)
The famous three words, though, through and thought. In Dutch: toch, door, dacht.
Here you can see the gh is in Dutch ch and it is pronounced in Dutch as well.
The word for country in Vietnamese
quốc gia, Japanese 国家(Kokka), Mandarin Chinese 国家 (Guo jia)
The Turkish mi represents 吗 in Mandarin Chinese. Water in Turkish, su, Mandarin Chinese (shui)
Now in Korean 지금 (jigeum), in Cantonese 而家 (ji gaa).
But maybe there would be more relations between languages. I am not familiar with other languages.
Also if you have time you can read nihao.jouwweb.nl
I don’t know how much Mandarin Chinese you would understand. Maybe cool to read.