English nouns, determiners, countability, specificity

When English speakers use a noun word, they indicate its specificity with a combination/selection of forms, inflections, determiners–forms being the syntax pattern it follows, uncountable or countable one, and specificity being:

generic <> non‑generic (unidentified) <> non‑generic (identified) <=> Proper

Note that forms may be one of subtle differences in meaning or entirely different ones, for example, good part of text‑related words such as letter, note, or text itself. Also note that non‑generic (identified) and Proper sense is not so much apart as can be seen in the example of, the sun, Mother, Central Park.