44. What is a free morpheme? What is a bound morpheme?
A “free morpheme” is a morpheme that constitutes a word by itself, such as ‘bed”, “tree”, etc. A “bound morpheme” is one that appears with at least another morpheme, such as “-s” in “beds”, “-al” in “national” and so on. All monomorphemic words are free morphemes. Those polymorphemic words are either compounds (combination of two or more free morphemes) or derivatives (word derived from free morphemes).

45. What is a root ? What is a stem? What is an affix?
A “root” is the base form of a word that cannot be further analyzed without total loss of identity. In other words, a “root” is that part of the word left when all the affixes are removed. “Internationalism” is a four-morpheme derivative which keeps its free morpheme “nation” as its root when “ inter-”, “-al” and “-ism” are taken away.
A “stem” is any morpheme or combination of morphemes to which an affix can be added. It may be the same as, and in other cases, different from, a root. For example, in the word “friends”, “friend” is both the root and the stem, but in the word “friendships”, “friendships” is its stem, “friend” is its root. Some words (i. e., compounds ) have more than one root ,e. g., “mailman” , “girlfriend” ,ect. An “affix” is the collective term for the type of formative that can be used, only when added to another morpheme(the root or stem). Affixes are limited in number in a language, and are generally classified into three subtypes: prefix, suffix and infix, e. g. , “mini-”, “un-”, ect.(prefix); “-ise”, “-tion”, ect.(suffix).

46. What are open classes? What are closed classes?
In English, nouns, verbs, adjectives, and adverbs make up the largest part of the vocabulary. They are “open-class words”, since we can regularly add new lexical entries to these classes. The other syntactic categories are, for the most part, closed classes, or closed-class words. The number of them is hardly alterable, if they are changeable at all.

47.  What is lexicon? What is word? What is lexeme? What is vocabulary? Lexicon? Word? Lexeme? Vocabulary?
“Lexicon”, in its most general sense, is synonymous with vocabulary. In its technical sense, however, lexicon deals with the analysis and creation of words, idioms and collocations. “Word” is a unit of expression which has universal intuitive recognition by native-speakers, whether it is expressed in spoken or written form. This definition is perhaps a little vague as there are different criteria with regard to its identification and definition. It seems that it is hard, even impossible, to define “word” linguistically. Nonetheless it is universally agreed that the following three senses are involved in the definition of “word”, none of which, though, is expected to cope with all the situations: (1) a physically definable unit, e.g. [it iz ‘w   ] (phonological), “It is wonder” (orthographic); (2) the common factor underlying a set of forms (see what is the common factor of “checks”, “checked”, “checking ”, etc.); (3) a grammatical unit (look at (1) again; every word plays a grammatical part in the sentence). According to Leonard Bloomfield, a word is a minimum free form (compare: a sentence is a maximum free form, according to Bloomfield). There are other factors that may help us identify words: (1) stability (no great change of orthographic features); (2) relative uninterruptibility (we can hardly insert anything between two parts of a word or between the letters). To make the category clearer we can subclassify words into a few types: (1) variable and invariable words; (2) grammatical and lexical words (e. g. to, in, etc., and table, chair, etc. By “lexical words” we mean the words that carry a semantic content, e.g., nouns, verbs, adjectives and many adverbs; (3) closed-class and open-class words. In order to reduce the ambiguity of the term “word”, the term “lexeme” is postulated as the abstract unit which refers to the smallest unit in the meaning system of a language that can be distinguished from other smaller units. A lexeme can occur in many different forms in actual spoken or written texts. For example, “write” is the lexeme of the following words: “write”, “write”, “wrote”, “writing”, and “written.” “Vocabulary” usually refers to all words or lexical items a person has acquired about technical or/and untechnical things. So we encourage our students to enlarge their vocabulary. “vocabulary” is also used to mean word list or glossary.