The standard method of creating words is to take a root morpheme and add affixes to it: (derivational morpheme) + root morpheme + (derivational morpheme) + (inflectional morpheme). The root morpheme is of course necessary while the morphemes in parentheses are optional. There are, however, other ways of creating words. Here is a brief discussion of the most common.

Compounding

Words can be created by taking two or more free morphemes and joining them together into compounds. This differs from affixing in that both elements are free morphemes. There are different ways of classifying compounds. The simplest way is to categorize them by the different parts of speech that are joined together. Thus we have the following types:

• Noun-Noun: bedroom, eyeball, peanut butter, airplane, fireplace, waterbed. In each of these, the first element modifies the second element, which is called the “head.” The head is the part which contains the basic semantic meaning of the compound (note that in some languages, the head comes before the modifier). Also note that our orthographic conventions regarding spacing does not have an effect on whether or not a word is a compound. Thus, peanut butter is a single compound, where butter is the head and is modified by peanut; peanut butter sandwich is also a compound, where sandwich is the head and peanut butter is the compound noun modifier. It makes no difference that we use spaces in writing these compounds but we don’t in bedroom.
• Adjective-noun: blackbird, redhead, blueblood. These can be differentiated from standard adjective + noun phrases primarily through stress (prosody). Thus, the phrase black bird is accentuated on both syllables: bláck bírd. The compound, describing a species of bird, such as Turdus merula, is accentuated only on the first syllable: bláckbird. As with noun-noun compounds, the head is the right-hand element while the first element is the modifier.
• Verb-noun: killjoy, cutthroat, breakfast. These are usually analyzed as a person or thing that X’s Y, where X is the verb and Y is the noun. Thus a killjoy is someone that kills joy. A breakfast is a meal that breaks one’s fast, and so on.

For less common categories of compounds, such as verb+verb, or adjective+adjective, you can review the wikipedia page on English compounds.

Another way of classifying compounds is into endocentric and exocentric groups.cMost of the examples above are endocentric compounds, that is, they contain the head within the compound itself. Thus, a bedroom contains the word room in it, and describes a room that has a bed in it. On the other hand, a redneck is not describing a neck that is red. This is an exocentric compound, because the “head” of the compound is a person, who (figuratively) happens to have a red neck. Compounds like this are more commonly called bahuvrihi compounds, after a Sanskrit word that means “much rice,” meaning a rich man (i.e., one who possesses much rice). Other examples in English are blueblood, redhead, blockhead, white-collar.

English also has many compounds whose elements were at one time free morphemes but which are no longer identifiable as such due to changes in the language. Thus, we have the following words in Modern English, which were originally compounds in Old English: orchard (plant-yard), lady (bread-kneader), lord (bread-guardian), nostril (nose-hole), window (wind-eye), hussy (house-wife), warlock (oath-breaker), gospel (good-story), garlic (spear-leak), and so on. Today, each of these would be considered simplexes rather than compounds.

Portmanteau words and blends

A portmanteau is a word that blends two morphemes into a single morpheme. Common examples are brunch (breakfast+lunch), ginormous (giant+enormous), and motel (motor+hotel). Newer examples are manscaping, mansplaining, spork, jeggings, brony, Brangelina, sexting, etc. Sometimes these are also called blends, and some linguists distinguish between blends and portmanteaux.

Some people consider the following morphemes under the category of portmanteaux rather than suffixing: –thon, -gate, -lympics, -mageddon. This may be partially correct, but they may be on their way to becoming suffixes. With portmanteau words there is a blending of phonemes from each word into a single morpheme. Consider the word marathon, originally a place name, but introduced into English in 1896 to describe a long race. We can add the end of this word to the beginning of a word such as television to get telethon, describing an especially long television program. But many words to which –thon can be added are not truncated: consider walkathon or Toyotathon. In these examples, -(a)thon acts more like a suffix than a blend. In fact, the word walkathon was first used in 1931, 18 years before telethon was first used. Similarly, –gate no longer indicates any connection with the Watergate hotel, but simply means “political scandal,” and is usually added to complete morphemes.

The morpheme –lympics also seems to act midway between a portmaneau and a suffix, since the primary use is in the word paralympics, a clear blend of paraplegic and olympics. We also have the Laff-A-Lympics and something called the E-lympics, both of which are based on Olympic-style contests. Its use in these newly-created words suggests a productive quality that is not usually found in other portmanteau words (i.e., we have the word brunch, but we don’t find *brinner or *brupper, let alone *bridnight-snack).

Reduplication

English does not currently use reduplication, but it used to. Reduplication was a primary method of creating the past tense of verbs, as you might know if you happen to have studied Greek, Sanskrit, Latin or an early Germanic language like Gothic. In Gothic the verb slepan “to sleep” formed its past tense sai-slep, by reduplicating the initial s- into a new syllable at the front of a word. The only word in (sort of) modern English which preserves a trace of reduplication is the very old-fashioned word hight, meaning “to be named,” which you will see if you read Chaucer or Spenser or some particularly archaic-sounding 19th-century poetry. If you know German you will recognize it as the very common word heißen. The in the middle of the word was originally the beginning of the word, and the initial hi- was the reduplicating syllable. Otherwise all traces of reduplication have been erased from English.

Morpheme Internal Change (also called apophony)

Although most English nouns and verbs add inflectional suffixes to the end of the root morpheme to signify different grammatical functions, there are many that make internal changes to the morpheme instead. There are two types of morpheme internal change in English.

• Umlaut or mutation: We discussed mutation briefly at the end of the section on phonology. These words are produced by a front mutation of the vowel. For example, while most nouns make their plurals by adding the inflectional morpheme –s, others change the vowel within the base morpheme: foot/feet, tooth/teeth, goose/geese; mouse/mice, louse/lice; and man/men, woman/women.
• Ablaut or Gradation: While most verbs make the past tense by adding an –ed morpheme, there are a large number that make vowel changes to form tenses: drive/drove/driven, bite/bit/bitten, ring/rang/rung, steal/stole/stolen, etc.

Suppletion

Suppletion is not so much the creation of a new morpheme as the substituting of one morpheme for another. So, while most adjectives make comparative and superlative forms by adding the inflectional morphemes –er and –est, such as tall, tall-er, tall-est, others simply use an entirely different, unrelated morpheme. The comparative and superlative forms of good are not *gooder and *goodest but better and best. These morphemes are not formed from good at all but from an archaic adjective bet that we no longer use. Some verbs do this too. The past tense of go is went, originally the past tense of the somewhat obsolete verb wend. The verb to be has three originally different verbs in it: the be forms, the am/is forms and the was/were forms. One tends to find suppletion in only the most common of words.