Spittle is the liquid in your mouth — what we normally call saliva or, in plain speech, spit. All three words point at the same stuff, but they do not feel the same. Spit is the everyday word. Saliva is the medical or scientific one, the word a doctor or a biology book uses. Spittle is the literary one, and it almost always carries a picture with it: spittle is saliva you can see, usually where you would rather not — at the corner of an old man's mouth, flying out when someone shouts in anger, on the chin of a baby or a sick person. Because of that, spittle nearly always sounds unpleasant or pitiful. You would not say 'my spittle' about your own mouth in a normal sentence; you would say spit. Writers reach for it to make a scene physical: 'spittle gathered at the corners of his lips as he ranted'. It is uncountable, and it is not common in speech at all — you will meet it in novels, in older translations of the Bible, and in vivid journalism. There is also a completely separate, rare gardening sense (a spit or spade's depth of soil), which you can safely ignore.

口水、唾液（帶畫面感的文學用字——通常是看得見、令人不適的那種口水，例如嘴角的白沫）。日常說 spit，醫學說 saliva。