I don't think, if recollection serves me right, that any emphasis on the association with 'yoke' was made much of in either the GD or French esoteric schools - at least, not with the importance that Crowley gave to it. However, the connection of Aleph with Yoke is certainly pre-1900.
The Aleph as yoke appears in Jewish literature - and as a pictogram of such was used to teach the letter to children. For example the poet Hayim Nahman Bialik (1873 - 1934) recalling his school day explains how the teacher showed him a card with with the letter Aleph on it: “Do you see here the wooden yoke with two buckets?” “Yes, I see.” “Well, that is called ‘Aleph’. Repeat: what is the name of this symbol?” “Marrusya,” answered the child. As it happened, just at that moment when he recognizes the wooden yoke and the buckets, he also sees the Polish water carrier Marrusya, who handles such an instrument, and the teacher was helpless to persuade the child to connect the word “Aleph”, which has no meaning for the pupil, with this symbol.”
My Gaze is Turned Inward: Letters 1938-1943 by Gertrude Kolmar p.65
A search of pre-1900 books on google gives several English* sources that describe the letter Aleph as representing ox horns with yoke - and the relevance of the yoke (the vau between the two yods - or the crossbar of the Roman 'A' considered as inverted horns 'V') is linked/associated with meanings to do with guidance, learning, teaching, teacher, leader.
Aleph as chief, leader, duke etc., can be found in numerous pre-1900 biblical Hebrew dictionaries, lexicons, commentaries. For example see Gen. 3:18 (Variously translated as Duke (KJV) or chief). Aleph also means one thousand, and as a Roman 'centurion' was leader of a 'century' (tribe, group of soldiers), so was an 'Aluph' a 'thousander' chief/leader/father of a tribe/clan/family.
Word: אלוף
Pronounc: al-loof'
Strong: #H441
Orig: or (shortened) talluph al-loof'; from 502; familiar; a friend, also gentle; hence, a bullock (as being tame; applied, although masculine, to a cow); and so, a chieftain (as notable, like neat cattle):--captain, duke, (chief) friend, governor, guide, ox. #H502
Use: TWOT-109b Adjective Masculine
GR Strong: #G172 #G747 #G1016 #G1319 #G2231 #G2232 #G2233 #G3609 #G5384 #G5506
1) tame, docile
2) friend, intimate
3) chief
Kwaw
* In French sources too:
La première lettre de l'alphabet s'appelle aussi de ce nom parce que c'est une tête ou un joug de bœuf qui a servi de type primitif à ce caractère. Encyclopédie théologique, Volume 7, Issue 2 by J.P. Migne, 1846.
Gebelin too, in Monde Primitif 1773** says that (in western languages, derived from the semitic) there is a character representing the Ox under the yoke, representing nature and the work of the plow (or the ploughman - my French isn't quite up to it so I may have misconstrued the gist) :
quote
"Celui-ci n’est donc qu’une épithète, une allusion, mais des plus naturelles, qui peint le Bœuf comme un animal dompté & réduit à l état de domesticité par l’homme qui lui aprit à plier sous le joug & à le seconder dans l’Art par excellence. C’est toujours par cette idée qu’on peint le Bœuf, & que le caractérisent les Poètes dans les tableaux ou ils peignent la Nature & les travaux du Laboureur."
(It is therefore not (?) an epithet, an allusion, but more naturally, that image of the Ox as tamed & reduced to domesticity by Man, who taught him to bend under the yoke & assist in the art par excellence. It is always with this idea that the Ox is painted, and that the Poets characterize in tableau or paint Nature & the work of Plougher.)
He also mentions the meaning of understanding/learning, in both senses of to instruct/teach and to be instructed/learn (which is associated with the meaning 'yoke', the young untamed ox being yoked with an older tamed ox to learn from the lead of the trained Ox):
quote:
"A ne sut donc pas à la tête de l’Alphabet, parcequ’il désignoit un Bœuf, mais il désigna un Bœuf parce qu’étant à la tête de l’Alphaber , il signifioit aprendre, dans les deux sens d’instruire & d être instruite."
(It was not known at the head of the alphabet because it designated an ox, but because, being appointed at the head of the Alphabet, the Ox signified learning, and that in both senses of to instruct/teach & to be instructed/learn.)
In Grand dictionnaire universel du XIXe siècle: Français, historique ..., Volume 1 , 1864
by Pierre Larousse, under an article on the history of the alphabet, the names and meanings of the Hebrew letters are given by and large much as the GD:
Aleph - bœuf, éléphant
Beth - maison
Ghimel - chameau
Daleth - porte
Hé - trou
Waw - clou
Zaïn - arme
Khet - clôture (de bétail)
Teth - serpent, main, poing
Iod - main
Caph - creux de la main
Lamed - garrot
Mim - eau
Nounn - poisson (dialecte araméen)
Samech - appui
Ayn - œil
Phé - bouche
Tsad - pêcher chasser hameçon, hibou
Qof - nuque (en arabe colline)
Resch - tête
Schin ou Sin - dent
Tau - signe en croix, joug
**NB: 1773 volume of Monde Primitif - not to be confused with the later volume in which the essays on tarot appeared.