The word is related to Quenya ëala ("being"), and seems to be related to the Quenya verb ëa "be, exist". It has been suggested that -la is the present participle ending of verbs (cf. "-ing"; but Quenya -la only forms adjectival participles)
Quenya
ëala
being, spirit
ëala
noun. spirit (not incarnate), being
ëalar
ëalar
ëa
eä
ëa (1) (sometimes "eä")vb. "is" (CO), in a more absolute sense ("exists", VT39:7/VT49:28-29) than the copula ná. Eä "it is" (VT39:6) or "let it be". The verb is also used in connection with prepositional phrases denoting a position, as in the relative sentences i or ilyë mahalmar ëa "who is above all thrones" (CO) and i ëa han ëa "who is beyond [the universe of] Eä" (VT43:14). Eä is said to the be "pres[ent] & aorist" tense (VT49:29). The past tense of ëa is engë (VT43:38, VT49:29; Tolkien struck out the form ëanë, VT49:30), the historically correct perfect should be éyë, but the analogical form engië was more common; the future tense is euva (VT49:29). See also ëala. Eä is also used as a noun denoting "All Creation", the universe (WJ:402; Letters:284, footnote), but this term for the universe "was not held to include [souls?] and spirits" (VT39:20); contrast ilu. One version of Tolkien's Quenya Lord's Prayer includes the words i ëa han ëa, taken to mean "who is beyond Eä" (VT43:14). Tolkien noted that ëa "properly cannot be used of God since ëa refers only to all things created by Eru directly or mediately", hence he deleted the example Eru ëa "God exists" (VT49:28, 36). However, ëa is indeed used of Eru in CO (i Eru i or ilyë mahalmar ëa** "the One who is** above all thrones") as well as in various Átaremma versions (see VT49:36), so such a distinction may belong to the refined language of the "loremasters" rather than to everyday useage.
eä
Eä
Eä was the word spoken by Eru Ilúvatar by which he brought the universe into actuality.
návë
being
návë "being", *"to be", infinitive (or gerund) of ná; see ná #1. (PE17:68)
návë
noun. being
The gerund (verbal noun) of ná- “to be” (PE17/68), so “being” as in “the state of being” rather than “a living being”.
ëala noun "being, spirit" (pl. ëalar is attested), spirits whose natural state it is to exist without a physical body, like Balrogs (MR:165). The word apparently originates from the participle of ëa, q.v.