The Mother Letters: Aleph Mem and Shin
עשר ספירות בלי מה ועשרים ושתים אותיות יסוד שלש אמות ושבע כפולות ושתים עשרה פשוטות:
They consist of a decade out of nothing and of twenty-two fundamental letters. He divided the twenty-two consonants into three divisions : 1) three אִמּוֹת mothers, fundamental letters or first elements ; 2) seven double ; and 3) twelve simple consonants.
(חמש שלש אותיות מן הפשוטות חתם רום ברר שלש וקבען בשמו הגדול יה"ו. וחתם בהם שש קצוות) [הנוסחא הנכונה: בירר ג' אותיות מן הפשוטות בסוד ג' אמות אמ"ש וקבען בשמו הגדול וחתם בהם ו' קצוות, חמש חתם רום] ופנה למעלה וחתמו ביה"ו. שש חתם תחת ופנה למטה וחתמו ביו"ה. שבע חתם מזרח ופנה לפניו וחתמו בהי"ו. שמנה חתם מערב ופנה לאחריו וחתמו בהו"י. תשע חתם דרום ופנה לימינו וחתמו בוי"ה. עשר חתם צפון ופנה לשמאלו וחתמו בוה"י:
He selected three consonants from the simple ones which are in the hidden secret of three mothers or first elements: א"מ"ש air, water and ether or fire. He sealed them with spirit and fastened them to His great name and sealed with it six dimensions. 5) He sealed the height and turned towards above, and sealed it with יהו. 6) He sealed the depth, turned towards below and sealed it with היו 7) He sealed the east and turned forward, and sealed it with ויה 8) He sealed the west and turned backward, and sealed it with והי 9) He sealed the south and turned to the right and sealed it with יוה 10) He sealed the north and turned to the left and sealed it with הוי.
עשרים ושתים אותיות יסוד שלש אמות שבע כפולות ושתים עשרה פשוטות. שלש אמות אמ"ש יסודן כף זכות וכף חובה ולשון חק מכריע בינתים:
The foundations are the twenty-two letters, three 'mothers', seven 'double', and twelve 'single letters'. Three 'mothers', namely Aleph, Mem, Shin, represent Air, Water, and Fire: Aleph mute as Water, Shin hissing as Fire, and Mem as air of a spiritual type, is as balance, standing erect between them and pointing out the equilibrium which exists, speaking.
שלש אמות אמ"ש יסודן כף חובה וכף זכות ולשון חק מכריע בינתים:
The three mother [letters] Aleph, Mem, and Shin, their foundation is a pan (of a scale) of culpability and a pan of merit, and the tongue of decree decides between them.
שלש אמות אמ"ש סוד גדול מופלא ומכוסה וחתום בשש טבעות וממנו יוצאים אש ומים מתחלקים זכר ונקבה: שלש אמות אמ"ש יסודן ומהן נולדו אבות שמהם נברא הכל:
The three mothers - Aleph, Mem, Shin - a mighty mystery, most occult and most marvelous, sealed as with six rings, and from them proceed Fire, Water, [and Air]; these are subsequently differentiated into male and female. Three mothers - Aleph, Mem, Shin, their foundation. And from them were born fathers and all was created from them.
שלש אמות אמ"ש בעולם אויר מים אש שמים נבראו תחלה מאש וארץ נבראת ממים והאויר מכריע בין האש ובין המים:
The three mother letters - Aleph, Mem, and Shin - are air, water, and fire in the world. Heaven is created from Fire [the shin in shamayim]; the Earth from Water [the mem in mayim]; and the Air [the aleph in ’avir] which decides between the fire and the water.
שלש אמות אמ"ש בשנה אש ומים ורוח חום נברא מאש קור ממים ורויה מרוח מכריע בינתים. שלש אמות אמ"ש בנפש אש ומים ורוח ראש נברא מאש ובטן נברא ממים וגויה נברא מרוח מכריע בינתים:
During the year, or in regards to time in general, these three mothers represent Hot, Cold, and Warm. The hot from the fire, the cold from the water, and the warm from the spiritual air, which again is an equalizer between them. These three mothers again represent in the Microcosm human form, male and female; the Head, the Belly, and the Chest. The head from the hot fire, the belly from cold water, and the chest from the warm air that lieth between them.
שלש אמות אמ"ש חקקן וחצבן וצרפן וחתם בהן שלש אמות בעולם ושלש אמות בשנה ושלש אמות בנפש זכר ונקבה:
These three mothers did He create, form, and design, and with the three mothers combine in the world, and in the year, and in Man, both male and female.
המליך אות אל"ף ברוח וקשר לו כתר וצרפן זה עם זה וחתם בהן אויר בעולם ורויה בשנה וגויה בנפש זכר באמ"ש ונקבה באש"ם:
He caused Aleph to reign in the air, and crowned it, and combined one with the other, and with these He sealed the Air in the world, the warmth of the year, and the chest (the lungs) in man; the male with Aleph-Mem-Shin, the female with Aleph-Shin-Mem.
המליך אות מ"ם במים וקשר לו כתר וצרפן זה עם זה וחתם בהן ארץ בעולם וקור בשנה ובטן בנפש זכר ונקבה זכר במא"ש ונקבה במש"א:
He caused Mem to predominate in Water, and crowned it, and combined it with others, and formed Earth in the world, cold in the year, and the belly in the soul, male and female, male with Mem-Aleph-Shin and female with Mem-Shin-Aleph.
המליך אות שי"ן באש וקשר לו כתר וצרפן זה עם זה וחתם בהן שמים בעולם וחום בשנה וראש בנפש זכר ונקבה [זכר בשא"מ ונקבה בשמ"א, (כ"ה בנ"י)]:
He caused Shin to reign in Fire and crowned it, and He combined one with the other, and sealed them, as heaven in the universe, as heat in the year, and as the head of Man and Woman. [Male with Shin-Aleph-Mem and female with Shin-Mem-Aleph.]
וכל אשר ירבו השלש יסודות אמ"ש להתקשר בשרשין דלהון כנ"ל. יתרבה אורן בפנימיותן ובהקיפן ויזדככו כל הגוף שמעפר שלא יהא שום עצלות וכבדות באברי הגוף. ויהיה רץ כצבי וקל כנשר לעשות רצון הקדוש ב"ה. כענין שכתוב בזוהר פנחס רכ"ה א'. לב איהו זכיך מכלא. מינה כל טב וכל בריאותה דשייפין כלהו. וכל תוקפא וכל חדוה וכל שלימו דאיצטריך לכל שייפין. ובזוהר ויקהל קנ"ח ב'. ת"ח בשעתא דבר נש שוי רעותיה לגבי פולחנא דמאריה ההוא רעותא סליק בקמייתא על לבא דאיהו קיומא ויסודא דכל גופא. ולבתר סליק ההוא רעותא על כל שייפי גופא ורעותא דכל שייפי גופא ורעותא דלבא מתחבראן כחדא. ואינון משכין עלייהו זיהרא דשכינתא לדיירא עמהון. וההוא ב"נ איהו חולקא דקב"ה:
And to the increasing extent that the three elemental letters alef, mem and shin connect to their roots (as previously mentioned), their light will increase, within them and surrounding them, and the entire body that comes from dust will be purified so that there won’t be any laziness nor heaviness in the limbs/organs of the body. And it will be able to run like the gazelle and be as light as the large bird of prey476Heb.: v’y’hee-yeh rahtz ka-tzvee v’kal ka-nehsher to do the will of the Holy One (blessed be He), as it’s written in Zohar (Pinkhas 225a): “The heart is more pure than all the others; from it comes all the good and the healthiness for all the limbs/organs, and all the strength, all the delight and the wholeness needed for all the limbs/organs”. And in Zohar (Va-yahk-heil 198b): “Come and observe: When a person sets his will in accord with the Master’s service, that will ascends first to the heart, which is the maintainer and the foundation of the entire body. And later that will ascends to all the limbs/organs of the body. The will of the heart and the will of all the limbs/ organs of the body join together as one, and they draw upon themselves the splendor of the Sh’kheena to dwell among them. And that person becomes a part of the Holy One (blessed be He).”

A note on building words from letters:

The hebrew alphabet is more than a writing form. Words are called Teivot, which has the connotation of box, or container.

A word is a container of meaning, stemming from the building blocks of creation. In Genesis, the creation of all existence is described as sayings of God.(1) Our Sages teach that God formed the world through ten sayings. This book describes each letter of the aleph bet.

General concepts on root words:

In a shoresh, or root word, there are nearly always 3 main letters. The position of each letter describes the word’s meaning.

1st position—describes what is happening

2nd position—describes how it is happening

3rd position—describes where it is happening.

To illustrate: using the word חלד (cheled), we can see how this concept applies.

ח indicates a connection

ל signifies growth

ד signifies a limitation

Through this concept, the word cheled is seen to mean a connection occurring through growth, in a location, concept, or setting of limitation. For example, death is a moment of connection with the infinite through growth into a new phase, and it occurs through a limitation—death. After death, there is no more action a person can take. As such, death acts as a limiter.

Aleph:

Value: 1

mother letter

created from 3 letters: yod, vav, yod

relationship: keter

Phonetical classification: Guttural

Vowel point: Patakh

Signification of name: ox

Aleph is the beginning of the aleph bet. It is before everything. (2)

Aleph is the thesis, the first third of the basic concepts. (3) It is a silent consonant. (4)

Aleph never occurs as a suffix. As a prefix, it indicates first-person future.

The aleph looks like the brain. (5) The upper right yod is chokhmah, the upper right of the brain. The lower left yod is Hod. The line in the middle is a vav, representing the six sefirot in between.

mem

Value: 40

mother letter

created from:

relationship: Nukvah/externally daat, internally keter

phonetical classification: labial

Signification of name: water

Mem represents the present, which is the womb of the future.

The open mem is female, and the closed mem is male. The open mem is the womb, open from below.

The letter mem itself is spelled mem-mem (מם), including male and female. This is since it contains chokhmah and binah. (22)

The value of mem alludes to the 40 days in which the embryo is formed in the womb.

shin

Value: 300

mother letter

created from: vav, vav, zayin

relationship: confluence of netzakh+hod+yesod into malkhuth

phonetical classification: dental

Signification of name: tooth

The mother letters form the first, middle, and last letters of the aleph bet. Since tav is a double letter, the final mother letter is shin.

The mother letters represent 3 distinct states of consciousness: silence, harmonious, and static/white noise. The mother letters’ pronunciation depict this, and can be used to rapidly switch between states to climb. One climbs in a swaying right to left motion.

Shin signifies multitude of deeds with a unity of purpose. (29)

As a prefix, Shin means “that”; it connects and specifies. Its 3 heads represent the 3 basic concepts: thesis, antithesis, and synthesis. These 3 exist to bring a single goal: Malchuth of Ain Sof. (30) This is the single point at the bottom of the Shin. Shin is the answer to the why of creation.

In its form, Shin represents this by looking like the roots of a tree. Every branch of the tree can be the root of a new tree. (31)

Rabbi Jill Hammer teaches,

בַּעֲרָ֖א Baara (fire).

חוּשִׁ֥ים Chushum (feelings or senses).

חֹ֣דֶשׁ Chodesh (moon)

The final letters of their names are alef, mem and shin. The Sefer Y'tzirah, an ancient work of Jewish mysticism, calls these letters [which are the first, center and final letters of the Hebrew alphabet] the "three mothers of the universe.

https://feminismandreligion.com/2018/05/22/the-three-mothers-feminine-elements-and-the-early-kabbalah-by-jill-hammer/