Kaylee wrote:
So if a sound causes the vocal cords to vibrate, they are voiced? And when they aren't vibrating, they are voiceless?
Exactly, although I might not characterize the sound as "causing" the vocal cords to vibrate. Think of a sound as an abstract unit: it may have the
feature of voicing (like [z]) or it may not (like [s]).
Kaylee wrote:
So Aspiration is the sound between a stop consonant, right...?

Here's a simpler way to think about aspiration: put a piece of paper in front of your mouth and say the words "pit" and "spit". For "pit", there should technically be a "puff" of air that makes the paper rustle, although the force can vary between speakers. In contrast, there shouldn't be any puff of air in "spit". This is because the [p] in "pit" is aspirated (a common feature of "stops" at the beginning of a syllable in English), while the [p] in "spit" is unaspirated (a common feature for "stops" when they appear in a consonant cluster, like "sp-").
As Linguoboy noted, the main technical (phonetic) aspect of aspiration is that it
delays the beginning of voicing on a following vowel. This is called a delay in Voice Onset Time. Think of it as if you were pronouncing a short [h] after the [p]: [h] is
voiceless, so it takes slightly longer for your vocal cords to start vibrating when you shift to the vowel.
Kaylee wrote:
And sonorants are vowels? As well as /m/? and I think /l/?
A simple definition of sonorant is "a sound which doesn't have a lot of friction". Think of the sound [f]: it's a
fricative and there is a good deal of turbulence/friction when you pronounce it. Contrast this with sound like [n], [m], [l], etc., where there is next to no friction.
One interesting aspect of sonorants is that, due to their nature, they are frequently
syllabic, e.g. performing the function of vowels. Thus, words like "button" and "little" show syllabic forms of the sonorants [n] and [l] in the final syllable.