Gnomish
duilin(g)
noun. swallow
duilin
masculine name. Swallow
duilinc
noun. swallow
duil
noun. swallow
glindwil
noun. swallow
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
A noun in the Gnomish Lexicon of the 1910s for the bird “swallow” with variants glindwil and lindwil, a combination of G. glin “sound” and the suffixal form -wil of G. bil bird (GL/39, 54).