Derivation & inflection
Derivation in linguistics means creating a new word from one existing word (creating a new word from two or more words is called compounding or composition, which is rare in Arabic). An example of derivation in English is the creation of the abstract noun childhood from the concrete noun child (an example of compounding is breakfast which comes from the two words break and fast). A deverbal (or deverbative) derivative is a word derived from a verb. A denominal (or denominative) derivative is a word derived from a noun.
Inflection means changing the shape of a word in order to express a change in something like number, case, tense, voice, person, or mood. For example, sang and teachers are inflections of sing and teacher. Unlike derivation, inflection does not produce a new word but only a different grammatical form of the same word. The inflection of verbs is called conjugation, and the inflection of nouns is called declension.
The most common way for derivation and inflection is affixation, i.e. adding affixes to the word stem. An affix can be a suffix, a prefix, or an infix. Another way is reduplication, which means repeating the word stem or a part of it. A third way is vowel mutation (also called vowel gradation, ablaut, and by many other names), which means changing vowels in the word stem, as in the English inflections sang and ran of sing and run.
More than one way may be used simultaneously, e.g. the past participle written differs from write both by having a suffix and by having a different vowel quality in the stem. Likewise, the Arabic passive participle maktȗbuṋ مَكْتُوْبٌ “written” differs from kataba كَتَبَ “he wrote” by affixes and by vowel qualities in the stem.
Unlike English, Arabic makes extensive and brutal use of vowel mutation. The derivatives and inflections of one word look very different from each other—so different that it is impractical to define the root as containing anything but a series of consonants.
However, while vowel mutation is common in Arabic, it does not happen always. Some types of derivatives and inflections are made simply by adding an affix, e.g. ðahabiyyuṋ ذَهَبِيٌّ “golden” is derived from ðahabuṋ ذَهَبٌ “gold” just by adding the suffix –iyy to the stem. (The ending –uṋ is not part of the stem because it is an inflectional ending.)
A derivation method is productive if speakers of the language can naturally use it to create new words. An example in English is the derivation of actor nouns from verbs by adding the suffix –er, like eater from eat and hitter from hit. Languages typically have words derived in ways that are no longer productive. For example, English speakers know that freedom, boredom, kingdom, etc. must be derived from free, bore, king, etc., but no one will naturally try to make up a new word by adding a suffix –dom, so this suffix is unproductive.
Different types of derivatives and inflections in Arabic are made in similar ways.
Consider the following example.
|Root||Stem Ⅰ (G-stem) verb||Stem Ⅶ (n-stem) verb|
|he/it broke [something]||he/it became broken|
|he/it cut [something]||he/it became cut|
|he/it lowered [something]||he/it became low|
Perfective verbs of the pattern ʔ·inRaRaRa (were R means a radical) have a common meaning distinguishing them from basic verbs of the pattern RaRaRa. The first pattern (called Stem Ⅶ or the n-stem) has a middle voice meaning. An English example of a middle-voice verb is the verb broke in the sentence “The glass broke.” In this sentence the glass is both a semantic agent and patient, that is, it did the action and was affected by the action at the same time.
Just like how the pattern ʔ·inRaRaRa distinguishes perfective Stem Ⅶ verbs, many other types of derivatives and inflections have patterns distinguishing them. The different patterns are called ʔabniya·tuṋ أَبْنِيةٌ “structures” or ʔawzȃnuṋ أَوْزَانٌ “measures.” These patterns are given abstractly with the root fʕl فعل “do.” For example, the patterns RaRaRa and ʔ·inRaRaRa are given as faʕala فَعَلَ “he did” and ʔ·infaʕala اِنْفَعَلَ “he became done.”