@Bloodsong

I recommend the BG3 wiki for the best & most up-to-date information about BG3. https://bg3.wiki/wiki/Spells is the link to the page on spellcasting.

Specifically, Speak with Animals is a Ritual Spell, which when "cast outside of combat, they do not consume spell slots and are effectively free to cast."

Originally Posted by Bloodsong
i tried casting a few more spells, like animal understanding, goodberry, the shileighliegh thing (i know that's a cantrip). then suddenly, heal was greyed out.
see: https://prnt.sc/VYx-7nZV1f37

if i hover over it, it says ! action level 1 spell slot. and the square on the left under the roman I turns red. same for thunder-whack. but animal understanding is still castable?

i don't understand what the interface is trying to tell me. (and how come the right level 1 spell square never turns red?)
The interface is telling you that casting Cure Wounds (or Thunderwave) would cost a 1st level slot, but you are out of them for the day (until you long rest).

Originally Posted by Bloodsong
i'm not understanding the limits of what is going on. i "get" 2 level 1 spells, so... i only get to cast 2 spells each day/rest/turn/something? or i can cast each one two times?? or...?

are those squares supposed to turn red when i use one, and then if both are red, i'm out? i guess that wouldn't work when you can use dozens of spells at once.
When you start the day, all of those squares will be blue. The number of squares tells you how many of that level of spells you can cast that day. 2 spells TOTAL each day. E.g., one Cure Wounds and one Thunderwave, or two Thunderwaves.

Each time you cast a 1st level spell, one of those boxes will turn grey (indicating you've used it up). If you try to cast a spell for which you're out of slots, then the box will highlight red indicating that you don't have any of that resource.