Comm. NT:
1. The following words in §3 are not in PED: cakkhati (it relishes), rūpayati (it makes visible—only referred to under rūpa), sappati (it is emitted; pass. of sapati, to swear (Ud 45)), udāhariyati (it is uttered, lit. “is carried up to”), gandhayati (it is smelt), sūcayati (it betrays), rasati (it tastes). Be ed. of Vibh-a reads manayati (not in PED) for muṇāti in parallel passage.
Vism-mhṭ (p. 508) explains cakkhati (relishes) semantically by “tasting a flavour as in ‘relishing’ honey or sauce” and cites M I 503. Linguistically it connects the word with ācikkhati (to show).
Āyatanavitthārakathāvaṇṇanā
When a visible form (rūpa) undergoes, like the visible aspect of a chameleon, an alteration in appearance (colour) at times when [the mind is] dyed with greed or corrupted with hate, etc., it makes visible what state [is prevalent] in the heart (i.e. the mind) and makes that evident as though it were an actual visible object; the meaning is that it demonstrates it by giving it, as it were, a graspable entity (saviggaha).
Or the word rūpa means demonstration, and that is the same as evidencing.
Or the word rūpa can be regarded as evidencing of elements too, since it has many meanings.
Rūpayati (it makes visible) is a derivative (nibbacana) of the word rūpa that expresses appearance (colour), while ruppati (it is molested) is a derivative that expresses the materiality aggregate.
[As to sound] only the sound of words (vacana-sadda) would be covered by the meaning ‘is uttered (udāhariyati),’ and here sound is not only the sound of words, but rather all that can be cognized by the ear is what ‘is emitted (sappati)’;
the meaning is that by means of its own conditions it is emitted (sappiyati), is made cognizable by the ear.
(cf. also sappari, to crawl).
Āyatanavitthārakathāvaṇṇanā
“‘It evokes life (jīvitaṃ avhayati)’ owing to appetite for tastes in food (āhāra), which is the cause of life (jīvita), since the act of swallowing is rooted in approval of tastes. This is the linguistic characteristic of the word jivhā (tongue)”