Yule chapter 5

Phonology is the study of how sound are used in a language. Phonology itself is just one part of the language. It is amazing to know that people do not used certain sounds such as the nasilation (46). I was impressed to read that phonemes are considered as phonetic of the mind. I have never heard such thing before, I know that people can have thoughts, but not phonemes.
In my dialect there are some sounds that can be understand only by Mande people. Even if we are from the same country, it does not mean that you can automatically pronounce those sounds correctly. There are some sounds that you have to be taught how to pronounce it before you hit the right note.
By changing only one letter in a word, you systematically change the meaning of it. For instance, pat and fat, bell and bet.(50) This classification is called minimal pairs. The words have different meaning and differ from only one sound.
I wonder how sounds are memorized by people?