The category of case of nouns

Word cropping

We get the word "Thursday" from the Old English words meaning "Thor's day" (Thunresdaeg), Thor being the Germanic god of throwing hammers across the sky, creating thunder.
To most of us "Thurs" is now just a stem that is part of the name of a day, it's not a meaningful unit like "birth", "dream", "light" or "holy" which we combine with "day" to get "birthday", "daydream", "daylight" and "holiday". If I said, "I'm having a little Thursmo" or "I'm feeling Thursish" you'd probably conclude I am a bit midweek-weary, and wish the weekend would hurry up and come. You wouldn't expect me to start throwing hammers round the office.
Words that are in current English made of two or more morphemes can also sometimes be cropped but still carry the meaning of the longer word, which is how the prefix "diss" came to mean "disrespect". But this same cropping also happens to single-morpheme words e.g. "bro" was cropped to"brother", and is now being used as a morpheme in its own right, in words like "bromance".

Once-were-morphemes

Former Latin Masters and self-styled Language Mavens (let's call them FLMs) like to devise tests containing questions like "what does 'alb' mean?" which are supposed to elucidate who has had a Really Proper English Education. I think of these tests in the same category as the 1930s Australian immigration department language test, which was a dictation test. If the immigration officer wanted to exclude you, but you spoke English and all the other major European languages, the test could be administered in Scots Gaelic (click here if you don't believe me).
To answer the FLM test question "what does the English bound stem "alb" mean?", you either have to know some Latin or a derivative language like Italian or Spanish, or you have to think about what words in English containing "alb" (albino, albumen, albatross, albedo) have in common, while ignoring unhelpful words like "albeit", "balboa" and "album" (unless you know the first albums were white tablets on which events and names were written) and be able to isolate the common thread in meaning.
This is hard, and young children can't usually do it, plus whether in real life it helps anyone to know that "alb" means "white" is kind of arguable. It's not widely used to make new words, though if there is a sudden upsurge in the need for unique URLs in the dairy, detergent or dental industries, it might be. There's no morpheme "tross" meaning "bird" or "fly" or "burden". So to most of us, the English word "albatross" contains only one morpheme.

Which morphemes to teach, when?

With an overcrowded curriculum and diminishing marginal utility on some content, teachers wanting to teach spelling in a logical, patterned way need to decide which morphemes to teach, and in what order.
Without a whole-school spelling/word study curriculum which knits phoneme-grapheme correspondences (like the "ed" in "jumped" and the "est" in "slowest") with the meanings of morphemes (like the "ed" in "jumped" and the "est" in "slowest") there will inevitably be a lot of doubling up, gaps, and confusion. So I'm always a bit surprised how few schools have a whole-school spelling/word study curriculum.
In formal or academic text, we need the nominative or subject form of the pronoun after a linking verb: "It was he who represented the United Nations during the 1960s," "That must be she on the dock over there." In casual speech and writing, however, that sounds awfully stuffy. Imagine the detective who's been looking for the victim's body for days. He jimmies open the trunk of an abandoned car and exclaims, "It's she!" No self-respecting detective since Sherlock Holmes would say such a thing.
When the personal pronoun follows except, but, than, or as, you've got an argument on your hands. Traditionally, these words have been regarded as conjunctions and the personal pronoun that follows has been regarded as the subject of a clause (which might not be completed). Thus "No one could be as happy as I." (If you provide the entire mechanism of the clause — "as I [am]" — you see the justification for the subject form.) The same goes for these other conjunctions: "Whom were you expecting? who else but he?" "My father is still taller than she" [than she is].
Many grammarians have argued, however, that these words are often used as prepositions, not conjunctions (and have been used that way for centuries by many good writers). In a structure such as "My mother is a lot like her," we have no trouble recognizing that "like" is acting as a preposition and we need the object form of the pronoun after it. Why, then, can't we use "than" and "but" as prepositions in sentences such as "Dad's a lot taller than him" and "No one in this class has done the homework but me"? Such usage is now widely regarded as acceptable in all but the most formal writing. The same argument is sometimes used for the object form after as — "The coach is not as smart as me" — but this argument does not enjoy the cogency of using the object form after but and than.
Garner* argues that when the pronoun precedes the but phrase, the objective case should be used ("None of the students were interested but him"); when the but phrase precedes the verb, the subject case is appropriate ("None of the students but he were interested"). The argument goes that in the former case but is behaving as a preposition, in the second as a conjunction.⁸