Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
spit (vv.)
There are two different verbs, each with the infinitive spit, but with differing past tense and past participle forms. The strong verb spit, meaning “to expel saliva,” has two Standard past tense forms, spit or spat, and the same two forms are its Standard past participle as well, with spitten and spitted Nonstandard past participles. Spitted is the Standard past tense and past participle form for the weak verb spit, meaning “to place on a spit as for roasting.”
