That food looks so good i've got 口水!
Being basically 文盲 [wen2 mang2 = illiterate] -- I use computer software to help me write Chinese characters -- I especially appreciate the SIMPLE characters. These are the characters that mere mortals like me can actually remember how to write.
First, thank you Chinese language for including the word 口, pronounced kou3, which means mouth. Love it. It even looks like a mouth.
I can also handle the word 水 [shui3 = water]. It's just 4 strokes.
Put these two words together and you get 口水, mouth water... also known as.... SALIVA!!
I have no proof or research to back it up, but my sense is that things that have been around a long time (like saliva) tend to be expressed very simply in Chinese.