Or indeed, ancient Chinese! Which IIRC was non tonal.
There's some linguistic pattern where consonant clusters at the end of words get dropped, but their 'effect' on the vowel remains and that's how these kind of tones develop.
IIRC there's also two different kind of tones, pitch tones, and register tones....
There are also plenty of tonal languages outside East/Southeast Asia, in South Asia, Africa, Europe, North America, and that's just ones I know of.
Languages also switch, like ancient Greek.