Haha i have to agree with other posters that its definitely typically long/short for vowels, and then hard/soft for consonants (hard g in gate vs soft g in giraffe, same goes for the letter c in cage vs. cent). There are a ton of technical terms/specifics for each sound that can be made/used in a language, but if you aren’t a speech pathologist or a linguist it really doesn’t matter too much! Rule of thumb for vowels though is if the vowel “says its name” in the word, it’s a long vowel.

I’m in the field of speech pathology so I’m just gonna jump in here, the a in “jam” is not 100% a short vowel (like in “hat”) or a long vowel (where the vowel says its name, like in “same”). It’s actually a nasalized vowel (influenced by an n or m after it, like “ran/man” as opposed to “rat/mat”.) So that might be why it’s a little hard to identify the sound in “jam” 🙃