Thus the three classes of particles are not separated by absolute planes of demarkation.
The use of these particles as parts of the verb; the use of nouns, adjectives, adverbs, and prepositions as intransitive verbs; and the direct use of verbs as nouns, adjectives, and adverbs, make the study of an Indian tongue to a large extent the study of its verbs.
To the extent that voice, mode, and tense are accomplished by the use of agglutinated particles or inflections, to that extent adverbs and verbs are undifferentiated.
To the extent that adverbs are found as incorporated particles in verbs, the two parts of speech are undifferentiated.
To the extent that prepositions are particles incorporated in the verb, prepositions and verbs are undifferentiated.
To the extent that prepositions are affixed to nouns, prepositions and nouns are undifferentiated.
In all these particulars it is seen that the Indian tongues belong to a very low type of organization. Various scholars have called attention to this feature by describing Indian languages as being holophrastic, polysynthetic, or synthetic. The term synthetic is perhaps the best, and may be used as synonymous with undifferentiated.
Indian tongues, therefore, may be said to be highly synthetic in that their parts of speech are imperfectly differentiated.
In these same particulars the English language is highly organized, as the parts of speech are highly differentiated. Yet the difference is one of degree, not of kind.
To the extent in the English language that inflection is used for qualification, as for person, number, and gender of the noun and pronoun, and for mode and tense in the verb, to that extent the parts of speech are undifferentiated. But we have seen that inflection is used for this purpose to a very slight extent.