In 1912, in his very first eurythmy lessons, Rudolf Steiner describes the consonants as a reaction to external influence in contrast to the vowels that weave within and reveal this inner being.

G (Sagittarius, Jupiter)

But further I should try myself to picture an ugly, rejecting, revolting and disgusting, but for the time being, also self-contained, outer world down to the last detail and to imagine how he described this first, beautiful, peaceful, self-contained world.

One should experience oneself placed in these too, but only reluctantly and reluctantly putting one foot in front of the other, executing a calm, but clearly defensive hand movement against each of these unveiled ugliness. "Learn to perceive G as a defensive reaction."

K (Sagittarius, Jupiter)

And if this outside world is also roused from its calm by something and assumes a malicious, threatening attitude, then this defence must be strengthened, in short, the G must then become a K, a similarly targeted gesture as before with the F. K stands for G as F for D.

N (Pisces, Jupiter)

Rudolf Steiner showed me the N and made me imitate it. With this movement it would be just as clear to experience as with L and M that these are movements that one can observe in one's own larynx and its neighbouring organs and disenchant them in an imitative way.

Rudolf Steiner pulled his hand back just as flat, but probably a little more relaxed, than he had moved it forward before - as if he were touching something very sensitively.

Lory Maier Smits from her lessons with Rudolf Steiner, September 1912, GA 277a