Can an adjective modify a pronoun or an unmentioned subject in Latin?

Question

In English it's quite awkward to modify a pronoun with an adjective. You can say: 'He, angered, answered the door' but that's not recommended. I just assumed that that rule applied to Latin as well but I've seen enough cases of this rule broken that it must be the case that that is not a rule in Latin. So in this passage in Tibullus

Bī́squĕ dĭḗ rĕsŏlū́tă cŏmā́s tĭbĭ dī́cĕrĕ lā́udes
Ī́nsīgnī́s tūrbā́ dḗbĕăt ī́n Phărĭá.

The subject of 'debeat' is not mentioned but from the previous lines we know that it is 'she'. And according to the
http://web.philo.ulg.ac.be/lasla/ database lasla 'insignis' is nominative. Using the translation available and making changes to it, it seems that what is going on here is:

and twice in the day she, conspicuous, be bound to chaunt thy praise with loosened tresses amid the Pharian throng.

Or perhaps there is a way of turning adjectives into adverbs that I'm unaware of which would make it:

and twice in the day she be conspicuously bound to chaunt thy praise with loosened tresses amid the Pharian throng.

However, according to the Oxford Latin Dictionary 'insignis' is not an adverb.

######UPDATE

Someone pointed out in the comments that 'Delia' was the subject mentioned a few lines ago. So here's another example, here, the subject is 'ego' and it appears that the adjective 'supplex' modifies 'ego' and as far as I know 'supplex' is not an adverb. This is from Tibullus 1.2

Nṓn ĕgŏ tḗllūrḗm gĕnĭbū́s pērrḗpĕrĕ sū́pplex
Ḗt mĭsĕrū́m sānctṓ tū́ndĕrĕ pṓstĕ căpút.

which is translated in the Loeb edition as:

nor to crawl on suppliant knees along the earth and strike my head against the sacred door-posts.

I should mention though the LASLA database says that 'supplex' is dative not nominative but the dative form is 'supplici'. The PHI edition says that 'supplex' is correct and besides 'supplici' would ruin the meter. The OLD does have a note regarding 'supplex':

FORMS: ablative sg. ~ici or (especially in substantival use or in dactylic verse) ~ice; nominative and accusative neut. pl. not attested; genitive pl. probably always ~icum.

However, this seems to me to explain why 'supplici' can be nominative, not why 'supplex' can be dative. If 'supplex' is nominative and it modifies 'ego' then I would think the literal translation would be:

I, supplicating, do not crawl on the earth with the knees and strike my miserable head against the sacred post

Answer 1

The adjectives you refer to (insignis, supplex, also resoluta) are all functioning as secondary predicates. (For a complete explanation, see Pinkster, Oxford Latin Syntax, ch. 21.) A secondary predicate is a non-obligatory clausal constituent that makes an assertion about the subject in coordination with the primary predicate (main verb). Secondary predicates can be adjectives (and phrases), quantifiers, nouns (and phrases), or participles (and phrases).

The role of the secondary predicate and your question, whether it can be used with a pronoun, are both illuminated by the most famous lines of Latin literature:

Arma uirumque cano, Troiae qui primus ab oris
Italiam fato profugus Lauiniaque uenit
litora

In these lines of Vergil, the subject of the relative clause is qui. The verb (primary predicate) is venit. In addition, there are two secondary predicates, primus and profugus. The person referred to by qui not only came, but came as the first and came as a fugitive. Even though one is an adjective and one is an adjective or noun, the constructions as a whole have adverbial force, because they describe in what condition or manner the subject was at the time of the primary predicate.

The use of adjectives as secondary predicates is extremely common in poetry, because of their concision and because, for various reasons, adverbs are relative scarce in poetry (OLS, 21.4). The adjectives most commonly used as secondary predicates refer to the mental or physical condition of the subject. For example, Vergil writes: Arma amens capio (Frantic, I seize arms).

Finally, just for comparison's sake, there is one instance in which English very commonly uses the secondary predicate: "They arrived home safe." Note: not "safely." They were in a safe condition at the time they arrived home.