The headword as transmitted is the present indicative (and subjunctive) active, third person singular, of the contract verb flhnafa/w, "I chatter"; see generally LSJ s.v. The Suda follows the entry in Photius (phi222 Theodoridis); see also Hesychius phi605 (where there is a second glossing synonym, mwrologei=) and, more broadly, the scholia to Aristophanes, Knights 664, where e)flhna/fa occurs (web address 1).
Theodoridis does not mention (as Adler had) the complication introduced by another Aristophanic passage, Clouds 1475 (web address 2): this in most mss has the second person singular present active imperative flhna/fa, though with the variant flhna/fei in two, and in the more recent scholia that variant is glossed with flua/rei, as here; see n. 1 below. It must therefore be a possibility that Clouds 1475 lies behind the present entry.
See also phi 535: the related forms flh/nafos and flhnafi/a.
[1] The gloss is the present indicative active, third person singular, of the contract verb fluare/w, "I babble"; see LSJ s.v. and cf. phi 548.