A root in the Qenya Lexicon of the 1910s given as ᴱ√Ẏak “a head of cattle”, with derivatives ᴱQ. yak(k)o “ox” and ᴱQ. yaksi “cow” (QL/105). In the contemporaneous Gnomish Lexicon it had derivatives G. gach “a milch cow” and G. gagron “a yoke ox, bullock” (GL/38). I think it is worth positing a Neo-Root ᴺ√GYAK “cattle” to salvage these early words.
Early Primitive Elvish
aka
root. *intensive, excessive
ak’lā
noun. ray
ẏaka
root. a head of cattle
asaka
root. *waterfall
A root for “waterfall” in the Qenya Lexicon (QL/29) and Gnomish Lexicon (GL/17) of the 1910s. Later words for “waterfall” like S. lanthir (PM/349) probably make this root obsolete.
kara
root. do, make
kapa-
verb. to leap
A root in the Gnomish Lexicon of the 1910s whose derivatives have to with “extreme” and “excessive“ (GL/17). It’s probably related to the intensive prefix ᴱQ. aka- from the 1920s Early Qenya Grammar (PE14/81). Given the differences in later intensive prefixes and its clash with other roots like 1930s ᴹ√AK “narrow” and (Sindarin only) √AK “hostile return”, it is unlikely this root remained valid in Tolkien’s later conception of the languages.