A morpheme is the smallest meaningful token of a language.

A phoneme is the smallest sound unit that can produce a change of morpheme by modification.

Phonotactics are the rules of pronunciation of a language. Phonetics is a term often used with the same definition but since it is sometimes defined differently phonotactics is my preferred term. I've never heard or seen it defined otherwise and as a (very imperfect) speaker of ten languages I believe this to be a concept of paramount importance. It is the source of 'accents', it is a source of dialectization and it can be a source of misunderstanding.

Linguistics is really about spoken language. If you want to talk about alphabets, logographs or any of that scribbly stuff you might descend into semiotics. I like that stuff too.
This: 'ง' is an ng. Ngoh ngu if you prefer. I like it very much. Not only is it an aesthetically satisfying combination of g and n, not only does it acheive in one sensible character that one sensible sound, but it's a little reminiscent of a snake. In fact that's what ngu means in Thai. Yes, it's from the Thai alphabet. But the Thai alphabet comes from Sanskrit. I'll scribble more when I confirm its progenesis. If.
This: '毋' is wu. So is this: '無'. And this: '无'. These are not allophones. They're basically the same word. Same phonemes, same tones. Very slightly different definitions, 1 vs 2&3. An important word to me, one of them must be Joshu's 'wu'. Well, the last two are just the traditional and the simplified but maybe I'm identifying a problem with logographs, or ideographs or whatever you want to call this nightmare. I wanted to learn Mandarin. Now I'm not so sure.
This: 'н' is an n. Well, maybe not. Obviously not? But it's pronounced very similarly to the latin N. So we have to learn Cyrillic too? Hey, at least it's an alphabet.
How much is psycholinguistics affected by literacy? Can written 'Chinese' be 'reformed?' Should it be? Why might that be important? Are there storage and/or bandwidth limitations to the human learning, storage and retrieval of information, including language structures?

My first dissertation touches on some uses and abuses of language. I consider whether I should continue research from time to time. I generally keep myself busy other ways.