Here are defined the [phonetic/phonological] characteristics of nouns, verbs, prepositions, and particles, the four types of words, as they occur in combination [with the following words, as in the Saṁhitāpāṭha] and before pause [or in isolation, as in the Padapāṭha]. (p. 98)
- Deshpande (1997)

As Śākaṭāyana has explained for the Veda, the compounding, the disjoining of the compounded expressions, and the separation of words in the Padapāṭha, so will I explain the fourfold word – noun, verb, pre-verb, and particle. The word which expresses action is the verb. The word which names an object is said to be a noun. Words like “ca”, when they do not refer to an object, are particles. However, words like “pra” are pre-verbs. (pp. 478-479)
- Deshpande (1997)