The word for “butter” in the Qenya Lexicon of the 1910s was ᴱQ. manya derived from the early root ᴱ√MṆGṆ (QL/62) with the cognate G. mang “butter” from the contemporaneous Gnomish Lexicon (GL/56). A similar form ᴱQ. mingwe “butter” appeared in Early Qenya Word-lists of the 1920s (PE16/141, 145), along with an unrelated form ᴱQ. úle “butter” that also appeared as an adjective in the phrase masta {mingwea >>} úlea]] “bread and butter” (PE16/141). In contemporaneous Early Noldorin Word-lists of the 1920s, the Qenya word for “butter” was ᴱQ. telpe rather than having its usual meaning “silver” as in earlier and later writings (PE13/154).
Neo-Quenya: Of these forms, I prefer ᴺQ. manya for “butter” for purposes of Neo-Quenya since it has the clearest (Neo-Sindarin) cognate ᴺS. mang. I assume these words are derived from a Neo-Root ᴺ√MANGYA where ngy became ng in (Old) Sindarin but became ndy in Quenya and then developed into ny.
A Qenya word for “butter” in Early Noldorin Word-lists of the 1920s from primitive ᴱ✶t’lḗpe (PE13/154), a temporary repurposing of the form usually used for “silver”, which in this document was ᴱQ. telqe from primitive ᴱ✶kelekwé (PE13/140).