Gnomish
aigli
noun. bird
bil
noun. bird
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 word for “bird” in the Gnomish Lexicon of the 1910s appearing next to G. bilinc “sparrow”, but this word was deleted and the gloss for bilinc was expanded to “a small bird, especially sparrow” (GL/22-23). The form bil appeared in a couple other places in the Gnomish Lexicon (GL/23, 31), but seems to represent a “root” rather than a word. Tolkien indicated bil was derived from ᴱ✶du̯il (GL/31), but the exact mechanism whereby du̯- became b- isn’t clear, but a similar change is seen in 1920s ᴱ✶du̯ag- > ᴱT. baga- “beat” and ᴱ✶tu̯ak- > ᴱQ. pak- “apply, attach” (PE14/66).