Those writers on the human mind who have adhered to the doctrine of Ideas, and have been the advocates for the Spirituality of Thought, have insufficiently considered, or held in subordinate regard, Language; the prominent criterion, by which a human being is proudly elevated above the rest of the animated creation. Speech, and its representation by characters, are exclusively comprehensible by man; and these have been the sources of his vast attainments and rapid progression. The ear receives the various intonations that convey intelligence, and the characters or symbols of these significant sounds are detected by the human eye. Some of the more docile animals have been supposed capable of comprehending the meaning of a few individual words, but no one worthy of belief, has affirmed that they could understand a sentence or distinct proposition: still less, has any person, however confiding in the marvellous, ever ventured to assert that they were able to read. The important feature, and obvious utility of language, consists in the commutation of our perceptions for a significant sound or word, which by convention may be communicated to others, bearing a common and identical meaning. In this manner we become intelligible to each other, by the transmission and reception of these articulate and significant sounds. Words are not only the representatives of the perceptions we receive through the medium of our five senses, but likewise of many internal feelings, passions, and emotions, together with all that the _Mind_ (the aggregate of capacity and acquired intelligence) has elaborated. The result of this commutation renders the word the intelligible substitute for the thing perceived, so that the presence of the object recalls its name, and the name when uttered excites the immediate recollection of the absent object. This reciprocal substitution or mutual exchange, forms the basis, and affords a reason for Language. Whoever will take the trouble to watch the progress of the child from the commencement of its efforts to speak, will be surprised with its display of curiosity and intelligence. It feels delighted with the existence it enjoys, and with the power its senses possess to examine the objects of the world that surrounds it. Every organ, in succession, is occupied in noticing the wonders and mysteries that are presented. This incessant, but silent play of perception, proceeds until a sound, often repeated, interests the sense of hearing, and although at first dimly comprehended, is meant to represent some present object or person, and which, by an excitement little understood, urges the effort of imitation. The success of intelligible pronunciation impels it forward to other attempts, _vires acquirit eundo_, and in a time comparatively short, it accumulates a copious vocabulary. These are the incipient efforts to establish that commutation of the object of perception for the word, on which the structure of language is erected.