OM - the matrix of all the various sounds

"There are hundreds of words for God.
One thought is connected with a thousand words; the idea "God" is
connected with hundreds of words, and each one stands as a symbol for God.
Very good. But there must be a generalisation among all these words, some
substratum, some common ground of all these symbols, and that which is the
common symbol will be the best, and will really represent them all. In
making a sound we use the larynx and the palate as a sounding board. Is
there any material sound of which all other sounds must be manifestations,
one which is the most natural sound? Om (Aum) is such a sound, the basis
of all sounds. The first letter, A, is the root sound, the key, pronounced
without touching any part of the tongue or palate; M represents the last
sound in the series, being produced by the closed lips, and the U rolls from
the very root to the end of the sounding board of the mouth. Thus, Om
represents the whole phenomena of sound - producing. As such, it must be
the natural symbol, the matrix of all the various sounds. It denotes the whole
range and possibility of all the words that can be made. Apart from these
speculations, we see that around this word Om are centred all the different
religious ideas in India; all the various religious ideas of the Vedas have
gathered themselves round this word Om." excerpted from RAJA YOGA
by Swami Vivekananda