Some other words have more logical connections though, like for example the word "quick" is a short word with short syllables, and hence the word itself can seem quick to say, and the words "large" and "tiny" are spoken with large and tiny mouth movements, respectively.
Interesting. I never really thought of if like that, and you actually had me mouthing the words. However...

Anyway, I have noticed that I tend to often agree with Tolkien's choices of words for his invented languages in the "Lord Of The Rings" legendarium.
For example, for some reason I always felt that "rokko" is an incredibly fitting word for "horse", and I believe his Quenya words for "light" and "dark" are "calë" and "mornië", respectively.
...you lost me here. You only agree that those words "fit" the meaning because that's the word he made for them. For example if "calë" and "mornië" were dark and light respectively, not light and dark, then I expect you'd still say that they "fit". I mean we all know that a tree is a tree and a rock is a rock, but what if that wasn't the case and a rock was a tree and a tree was a rock - they'd fit because that's what we'd know them as.