The oral manner of articulation is naturally not sufficient to define a consonant.  The place of articulation must also be considered.  Contacts may be formed at a large number of points, from the root of the tongue to the lips.  It is not necessary here to go at length into this somewhat complicated matter.  The contact is either between the root of the tongue and the throat,[21] some part of the tongue and a point on the palate (as in k or ch or l), some part of the tongue and the teeth (as in the English th of thick and then), the teeth and one of the lips (practically always the upper teeth and lower lip, as in f), or the two lips (as in p or English w).  The tongue articulations are the most complicated of all, as the mobility of the tongue allows various points on its surface, say the tip, to articulate against a number of opposed points of contact.  Hence arise many positions of articulation that we are not familiar with, such as the typical “dental” position of Russian or Italian t and d; or the “cerebral” position of Sanskrit and other languages of India, in which the tip of the tongue articulates against the hard palate.  As there is no break at any point between the rims of the teeth back to the uvula nor from the tip of the tongue back to its root, it is evident that all the articulations that involve the tongue form a continuous organic (and acoustic) series.  The positions grade into each other, but each language selects a limited number of clearly defined positions as characteristic of its consonantal system, ignoring transitional or extreme positions.  Frequently a language allows a certain latitude in the fixing of the required position.  This is true, for instance, of the English k sound, which is articulated much further to the front in a word like kin than in cool.  We ignore this difference, psychologically, as a non-essential, mechanical one.  Another language might well recognize the difference, or only a slightly greater one, as significant, as paralleling the distinction in position between the k of kin and the t of tin.

[Footnote 21:  This position, known as “faucal,” is not common.]

The organic classification of speech sounds is a simple matter after what we have learned of their production.  Any such sound may be put into its proper place by the appropriate answer to four main questions:—­What is the position of the glottal cords during its articulation?  Does the breath pass into the mouth alone or is it also allowed to stream into the nose?  Does the breath pass freely through the mouth or is it impeded at some point and, if so, in what manner?  What are the precise points of articulation in the mouth?[22] This fourfold classification of sounds, worked out in all its detailed ramifications,[23] is sufficient to account for all, or practically all, the sounds of language.[24]