36. What are minimal pairs?
When two different phonetic forms are identical in every way except for one sound segment which occurs in the same place in the string, the two forms (i. e., word) are supposed to form a “minimal pair”, e.g., “pill” and “bill”, “pill” and “till”, “till” and “dill”, “till” and “kill”, etc. All these words together constitute a minimal set. They are identical in form except for the initial consonants. There are many minimal pairs in English, which makes it relatively easy to know what are English phonemes. It is of great importance to find the minimal pairs when a phonologist is dealing with the sound system of an unknown language.

37. What is free variation?
If two sounds occurring in the same environment do not contrast; namely, if the substitution of one for the other does not generate a new word form but merely a different pronunciation of the same word, the two sounds then are said to be in “free variation”. The plosives, for example, may not be exploded when they occur before another plosive or a nasal (e. g., act, apt, good morning). The minute distinctions may, if necessary, be transcribed in diacritics. These unexploded and exploded plosives are in free variation. Sounds in free variation should be assigned to the same phoneme.

38. What is complementary distribution?
When two sounds never occur in the same environment, they are in “complementary distribution”. For example, the aspirated English plosives never occur after [s], and the unsaturated ones never occur initially. Sounds in complementary distribution may be assigned to the same phoneme. The allophones of [l], for example, are also in complementary distribution. The clear [l] occurs only before a vowel, the voiceless equivalent of [l] occurs only after a voiceless consonant, such as in the words “please”, “butler”, “clear”, etc., and the dark [l] occurs only after a vowel or as a syllabic sound after a consonant, such as in the words “feel”, “help”, “middle”, etc.

39. What is the assimilation rule? What is the deletion rule?
The “assimilation rule” assimilates one segment to another by “copying” a feature of a sequential phoneme, thus making the two phones more similar. This rule accounts for the raring pronunciation of the nasal [n] that occurs within a word. The rule is that within a word the nasal consonant[n] assumes the same place of articulation as the following consonant. The negative prefix “in-“ serves as a good example. It may be pronounced as [in], [i] or [im] when occurring in different phonetic contexts: e. g., indiscrete-[    ] (alveolar) inconceivable-[    ](velar) input-[‘imput] (bilabial)
The “deletion rule” tells us when a sound is to be deleted although is orthographically represented. While the letter “g” is mute in “sign”, “design” and “paradigm”, it is pronounced in their corresponding derivatives: “signature”, “designation” and “paradigmatic”. The rule then can be stated as: delete a [g] when it occurs before a final nasal consonant. This accounts for some of the seeming irregularities of the English spelling.

40. What is suprasegmental phonology? What are suprasegmental features?
“Suprasegmental phonology” refers to the study of phonological properties of linguistic units larger than the segment called phoneme, such as syllable, length and pitch, stress, intonation.
 
41.  What is morphology?
“Morphology” is the branch of grammar that studies the internal structure of words, and the rules by which words are formed. It is generally divided into two fields: inflectional morphology and lexical/derivational morphology.

42. What is inflection/inflexion?
“Inflection” is the manifestation of grammatical relationships through the addition of inflectional affixes, such as number, person, finiteness, aspect, and case, which does not change the grammatical class of the items to which they are attached.

43. What is a morpheme? What is an allomorph?
The “morpheme” is the smallest unit in terms of relationship between expression and content, a unit which cannot be divided without destroying or drastically altering the meaning, whether it is lexical or grammatical. The word “boxes”, for example, has two morphemes: “box” and “-es”, neither of which permits further division or analysis if we don’t wish to sacrifice meaning. Therefore a morpheme is considered the minimal unit of meaning. Allomorphs, like allophones vs. phones, are the alternate shapes (and thus phonetic forms) of the same morphemes. Some morphemes, though, have no more than one invariable form in all contexts, such as “dog”, “cat”, etc. The variants of the plurality “-s” make the allomorphs thereof in the following examples: map-maps, mouse-mice, sheep-sheep etc.