Indicative phase of language. See [Language]
Indicative signs, or stage of language. See [Language]
Indo-European languages. See [Languages]
Infant. See [Child]
Inflectional. See [Languages]
Instinct, defined, [7];
of man and brutes compared, [7], [8]
Intellect of man and brutes compared, [9]
Introspection. See [Self-consciousness]
Isolating. See [Languages]