I'm a Spanish native speaker and to me, all these phonemes sound quite similar.
What are the little details that make these sounds different?
I'm a Spanish native speaker and to me, all these phonemes sound quite similar.
What are the little details that make these sounds different?
The position of the tongue (high, low, front, back) the length of the vowel and in the case of /aɪ/ the fact that it is made of two sounds merged together.
The sound in "cat" has the tongue further forward than in Spanish "papa", nearly as far forward as Spanish "les" but more open than "les" (as open as papa)
The sound in "up" has a similar tongue position to Spanish "no", but it isn't rounded, you don't purse your lips to say it.
The sound in car is similar to "papa" but longer (and slight further back).
The sound in high is a dipthong, made by blending from an a to an i sound.
In short they are different, and different from the Spanish vowels.
I agree with James K's answer, but I would add: