 Some verbs have irregular changes when they are in past tense. In this case, the verbs also have two morphemes. Words which are not related in form to indicate grammatical contrast with their roots are called suppletives.

     Free and bound morphemes

     Some morphemes constitute words by themselves. These morphemes are called free morphemes.

     Other morphemes are never used independently in speech and writing. They are always attached to free morphemes to form new words. These morphemes are called bound morphemes.

     The distinction between a free morphemes and a bound morpheme is whether it can be used independently in speech or writing.

     Free morphemes are the roots of words, while bound morphemes are the affixes (prefixes and suffixes).

     Inflexional and derivational morphemes

     Inflexional morphemes in modern English indicate case and number of nouns, tense and aspect of verbs, and degree of adjectives and adverbs.

     Derivational morphemes are bound morphemes added to existing forms to construct new words.

     English affixes are divided into prefixes and suffixes.

     Some languages have infixes, bound morphemes which are inserted into other morphemes.

     The process of putting affixes to existing forms to create new words is called derivation. Words thus formed are called derivatives.

     Conclusion: classification of morphemes

     Morphemes

     Free morphemes

     Bound morphemes

     Inflexional

     Derivational: affixes

     Prefixes: -s, -’s, -er, -est, -ing, -ed, -s

     Suffixes

     Formation of new words

     Derivation

     Derivation forms a word by adding an affix to a free morpheme.

     Since derivation can apply more than once, it is possible to create a derived word with a number of affixes. For example, if we add affixes to the word friend, we can form befriend, friendly, unfriendly, friendliness, unfriendliness, etc. This process of adding more than one affix to a free morpheme is termed complex derivation.

     Derivation does not apply freely to any word of a given category. Generally speaking, affixes cannot be added to morphemes of a different language origin.

     Derivation is also constrained by phonological factors.

     Some English suffixes also change the word stress.

     Compounding

     Compounding is another common way to form words. It is the combination of free morphemes.

     The majority of English compounds are the combination of words from the three classes – nouns, verbs and adjectives – and fall into the three classes.

     In compounds, the rightmost morpheme determines the part of speech of the word.

     The meaning of compounds is not always the sum of meaning of the components.

     Conversion

     Conversion is the process putting an existing word of one class into another class.

     Conversion is usually found in words containing one morpheme.

     Clipping

     Clipping is a process that shortens a polysyllabic word by deleting one or more syllables.

     Clipped words are initially used in spoken English on informal occasions.

     Some clipped words have become widely accepted, and are used even in formal styles. For example, the words bus (omnibus), vet (veterinarian), gym (gymnasium), fridge (refrigerator) and fax (facsimile) are rarely used in their complete form.

     Blending

     Blending is a process that creates new words by putting together non-morphemic parts of existing words. For example, smog (smoke + frog), brunch (a meal in the middle of morning, replacing both breakfast and lunch), motel (motor + hotel). There is also an interesting word in the textbook for junior middle school students – “plike” (a kind of machine that is like both a plane and a bike).