Free Morpheme and Bound Morpheme:

 Morphemes are classified into two types- free morphemes and bound morphemes. A free morpheme can stand alone as a complete word and still have meaning. For example: bag, book, goat, dog, is, and, but, beauty, cruelty, and so on.

Free morphemes are of two types- lexical or referential morphemes and functional or grammatical morphemes.

Lexical morphemes: lexical or referential morphemes carry the main meaning. These are very large in number and independently meaningful morphemes. They include nouns (such as tree, people, rice, length, dog), adjectives (such as kind, cruel, tall, short, wide), main verb (go, read, try, run), and adverbs (quickly, happily, shortly), etc.

Functional or grammatical morphemes: The grammatical morphemes are very limited in number and can also be used independently. They have little or no meaning on their own but demonstrate grammatical relationships in and between sentences. They usually include auxiliary verbs (for example, a, the, much, little, each, etc.), prepositions (in, to, into, up, below, etc.), and conjunctions (and, but, or, yet,etc).

Bound morphemes: 

Bound morphemes do not stand alone. It must be attached to a free morpheme to convey meaning. For example, some morphemes like boy, desire, gentle, and man constitute words by themselves. On the other hand, the morphemes like -hood, -ish, -ness, -ly, dis, un – are never words but always parts of words. These occur only before other morphemes. These morphemes are called prefixes or suffixes. These prefix and suffix morphemes are called bound morphemes because they cannot occur unattached, as distinct from free morphemes like man, child, sick, brave, allow, and so on.

There are two types of bound morphemes_ Inflectional morphemes and Derivational morphemes.

Inflectional Morpheme: An inflectional morpheme serves a purely grammatical function, such as referring to and giving extra-linguistic information about already existing meaning of a word, for example, number, person, gender, tense, case, etc. in English, there are only eight inflections- third person singular marker or verbs in present tense, as in speaks, teaches: regular plural marker, as in books, papers, mangoes; possessive marker ‘s/s’ as in James’s office; regular past tense marker, as in helped, borrowed, drew, played; past participle marker -en, as in driven, given, written; present participle marker -ing, as in driving, reading, giving, studying; comparative marker -er, as in faster, happier; and superlative marker -est, as in fastest, happiest, slowest, etc.

Derivational morpheme: Derivational morphemes are the morphemes that create new words, usually by either changing the meaning and /or the word category, or both. It can be divided into two classes: class maintaining morphemes and class changing morphemes. Class maintaining derivational morphemes stands for those suffixes that generate a derived form of the same class, such as -hood in boyhood and ship in scholarship. On the contrary, the class-changing derivational morphemes refer to those morphemes that produce a derived form of another class, such as -er in teacher, -ish in childish, or -al in national, etc.

Bound morphemes are divided into two parts and these are Bound roots and Affixes.

 Bound Roots: Bound roots include those bound morphemes which have lexical meaning when they are attached to other bound morphemes to form content words, for example, -‘ceive’ in receive, conceive; -‘tain’ in retain, contain; ‘plac’- in implacable, placate; ‘cran’- in cranberry, etc. It is noteworthy that bound roots can be prefixed or suffixed to other affixes.

Affixes: Affixes are bound morphemes which are usually marginally attached to words and that change the meaning or function of those words, for example, -ment in development, ‘en- in enlarge, ‘'s’ in John's, ‘-s’ in claps, ‘-ing’ in studying, etc. Affixes can be classified into two different ways: (i) according to their position in the word; and (ii) according to their function in a phrase or sentence.

According to their position in the word (or side of the word they are attached to), affixes are classified into prefixes, infixes, and suffixes.

Prefixes are bound morphemes added to the beginning of the word, for example, un- in unnoticed, a-in amoral, sub- in subway, etc.

Infixes are bound morphemes inserted within the words. There are no infixes in the English language, but in the languages such as Tagalog and Bontoc in the Philippines.

Suffixes are bound morphemes attached to the end of the word, for example, -able in noticeable, --less in careless, -s in seeks, -en in shorten, etc.

Again, according to the function affixes fulfil in the language, affixes are classified into derivational affixes and inflectional affixes.

Derivational affixes are the morphemes that create new words, usually by either changing the meaning and/or the word category or both. In English, derivational morphemes can be either prefixes or suffixes, for example, un-+ happy (adjective) = unhappy (adjective); re-+ classify (verb) = reclassify (verb); by-+ product (noun) = by-product (noun). The derivational morphemes can thus be divided into two classes- class-maintaining morphemes and class-changing morphemes. The class- maintaining derivational morphemes stand for those suffixes that generate a derived form of the same class, such as -hood in boyhood and -ship in scholarship. On the contrary, the class- changing derivational morphemes refer to those morphemes that produce a derived form of another class, such as -er in teacher, -ish in childish, -al in national, etc.

Inflectional affixes are the morphemes which serve a purely grammatical function, such as referring to and giving extra- linguistic information about the already existing meaning of a word, for example, number, person, gender, case, etc. For instance, the different forms of the verb speak are all considered to be verbs too, namely, speak, spoken, speaking. In a like manner, the comparative and superlative forms of the adjectivestrong are also adjectives, namely, stronger, strongest. In English, there are only eight inflections - third person singular marker of verbs in present tense, as in speaks, teaches; regular plural marker, as in books, oranges; possessive marker 's/s' as in John's house; regular past tense marker, as in helped, repeated; past participle marker -en, as in spoken, eaten; present participle marker -ing, as in eating, studying; con.oarative marker -er, as in faster, happier; and superlative marker -est, as in fastest, happiest.