In a later work he returns to the subject when speaking of the Lenape (Algonkin Delaware) dialect, and asks whether the rich imaginative power, of which it bears the evident impress, does not point to some youthful, supple and vigorous era in the life of language in general?[21-†] But he leaves the question unanswered.
§ 11. Classification of Languages.
The lower unit of language is the Word; the higher is the Sentence. The plans on which languages combine words into sentences are a basic character of their structure, and divide them into classes as distinct and as decisive of their future, as those of vertebrate and invertebrate animals in natural history.
These plans are four in number:
1. By Isolation.
The words are placed in juxtaposition, without change. Their relations are expressed by their location only (placement). The typical example of this is the Chinese.
2. By Agglutination.
The sentence is formed by suffixing to the word expressive of the main idea a number of others, more or less altered, expressing the relations. Examples of this are the Eskimo of North America, and the Northern Asiatic dialects.
3. By Incorporation.
The leading word of the sentence is divided and the accessory words either included in it or attached to it with abbreviated forms, so that the whole sentence assumes the form and sound of one word.