我是柠檬我总心酸我是洋葱我总流泪
[wŏ shì níng méng wŏ zŏng xīn suān wŏ shì yáng cōng wŏ zŏng liú lèi]
It means 'I'm lemon and I'm always heart-soured; I'm onion and I am in constant tears'. These lines use metaphorical language for emotional expressions (lemon implies a sour heart; onion makes one tear up).