The category of case of nouns

The comparative: is used to make adjectives that compare things, and written "er" e.g. funkier, lazier, redder.

The superlative: is like the comparative, only moreso, and written "est" e.g. funkiest, laziest, reddest.

Four inflectional suffixes are added to the ends of verbs:

• 
  Third person singular present tense: is the "s" verb agreement in "she sleeps", "he wakes" or "it lurks".
  
• 
  Simple past tense: is usually "ed" as in "it lurked" but we also have many irregular forms from good old Old English, like "she slept" and "he woke", where it is hard to say which bit of the word is the base word and which bit is the past tense, but there are still two meanings and therefore two morphemes.
  
• 
  Past participle: usually "en" as in "she has chosen" or "he had woken" or "ed" as in "they have danced" or "we have smashed", but there are again many irregular forms e.g. "I have slept", "you had crept" etc. There are many lists of irregular simple past and past participle verbs on the www, click here for one from the British Council.
  
• 
  Present participle: the "ing" that shows continuous action e.g. "she is carousing", "he was prancing". Note that these "ing" words can be used as adjectives e.g. "The prancing pony", or they can be used as nouns e.g. "Prancing has worn me out".
  

Then we have many more morphemes called derivational affixes, which go at the start of words (prefixes) or the end (suffixes) to change their meaning or word type. For example, we can add:⁷

• 
  "anti" before a noun adds the meaning "against" e.g. antiwar, anticlimax, antidote.
  
• 
  "ante" adds the meaning "before" as in antechamber, antecedent, antenatal (but beware, sometimes the meaning "ante" is spelt "anti" as in anticipate, antique)
  
• 
  "omni" adds the meaning "all/every", as in omnivorous, omniscient, omnibus.
  
• 
  "ist", "ian" or "eer" after a noun to add the meaning "one who…" e.g. pianist, dramatist, optometrist, politician, magician, musician, mountaineer, musketeer, engineer.
  
• 
  "vore" after a noun adds the meaning "eater", as in carnivore, herbivore, omnivore, locavore.
  
• 
  "gate" has within my lifetime become a suffix which turns a word into a scandal, as in Watergate, Camillagate and Wormgate (an Australian federal election debate controversy).
  
• 
  "er" after a verb to add the meaning "one who…" or "that which…" e.g. dancer, swimmer, repairer, can-opener, toaster, typewriter. However, "er" is not always a suffix when it appears at word endings – a brother is not someone who broths, and water is not a thing that wats,
  
• 
  "ity" after a verb to make it into a noun e.g. prosperity, equality, security.
  
• 
  "un" before a verb to reverse its action e.g. undo, unpack, unlace, unwind, unpick.
  
• 
  "ment" after a verb to turn a verb into a noun e.g. embarrassment,
  
• 
  "ly" after an adjective to make it into an adverb e.g. kindly, quietly, aggressively.
  
• 
  "ous" after an adjective to add the meaning "full of" or "possessing" e.g. joyous, nervous, spacious.
  

Both inflectional and derivational affixes are used productively to make new words. Children typically experiment with them a lot when learning to speak, making cute mistakes, e.g. "I runned and falled over", "It's the funnest", or "I scratched my legpit". Adults sometimes deliberately get them wrong for comic effect e.g. asking whether you've squozen the oranges.
These affixes also tend to have predictable spelling patterns, so that once you know how build words in spoken language using the suffix "ful", and you know how to spell words like "fearful", "joyful" and "wilful", I can tell you about something "squessful" and ask you to write it down, and you'll put FUL not FULL, FEL or something else. People learn the affixes in spoken language naturally, because that's how our brains are wired, but major spelling patterns like this should be taught, because spelling is a learnt skill, not a natural process.

Bound stems (sometimes called word roots)

There are a further set of morphemes in English which aren't words by themselves, but do carry specific meanings, and which can be made into new words by adding one or more prefixes or suffixes. These are called bound stems or word roots, linguists being rather keen on trees as metaphors for language structure.
For example, the stem "tele" means "far off" as in "telegram", "television" and "teleport". The stem "phon" meaning "sound" gives us "phoneme", "euphonium" and, if combined with the stem "tele", "telephone" (a bit like a compound word, but made out of two stems). The bound stem "vac" means "empty" as in "vacuum", "evacuate" and "vacant", even though it is not pronounced the same in all three. English tends to keep stems spelt the same even when their pronunciations vary considerably, think of the "anthrop" (meaning "man") in "anthropology" and "misanthrope". So it's useful to be taught some of the most common bound stems.