To be honest, and I diverge a little from 5e standards here... the concept of verbal components for spells hasn't ever really struck true with me *except* for casters who have learned their magic and the shaping of the weave through pure academia, and casters who entreat deities; that mainly means wizards and clerics.
Wizards have no innate magical ability (that is why they are wizards); they draw upon the weave and shape it by creating the arcane construction needed through an understanding of shapes, forms and sounds that cause these effects; they can't 'feel' the weave in the same way innate casters can. For them, having the full list of components makes a lot of sense; "this gesture, with these sounds, in this manner, manipulates the weave and actualises it this way" (Gale's weave scene is actually a really good depiction of this, in many ways), so their tendency may well be to speak with force and pronouncement, because they *must* be incredibly precise.
For those that entreat other beings, such as clerics, paladins, druids, and arguably warlocks as well, the need for vocalisation makes sense, absolutely, but the need for it to be forceful, precise and loud very distinctly does NOT. A cleric may cry out to their deity with force and fervour, certainly... but equally so they may clutch their symbol, close their eyes and whisper their prayer as they channel the powers they've been granted. As others mention, it should likely vary by spell type and situation. Sneaking characters incant quietly, characters engaged in pitched combat probably shout, characters casting charms and such should probably talk smoothly or whisper.
For casters with innate abilities, the concept of verbal components just feels completely off base... For a sorceress with power in her veins; power that, by definition of being a sorcerer, generally *has to be used*, or else it finds a way itself sooner or later... The idea that she must incant a specific line or string of syllables to release the effect she can evoke feels... to be blunt... stupid. At least it does to me. A sorcerer hasn't learned formulae and structure for the magic she evokes, and she hasn't spent hours in study perfecting the right syllables to shape the magic just so.
All that said... the idea that everyone must shout their lines at all times "because that's the way BG1 did it" is equally ridiculous. Let's get some context sensitivity in here, please.