Derivational Morphology of Assamese Lexical Word Categories

Word formation by derivation is very productive in Assamese. A significant amount of words in Assamese owe their origin to derivation. The analysis in this paper takes into account the derivational processes related with lexical word categories, and, numerous bound morphemes that are used in the derivational process in the language. This analysis helps us to understand some of the important aspects of Assamese morphology. These aspects are - role of class maintaining and class changing morphemes, derivation of word from synonyms, productivity of derivational morphemes, morphophonemic changes in root as a result of affixation of derivational morphemes, presence of allomorphs of various bound morphemes, ability of a morpheme to derive words from different word categories. The significance of this papers lies in the fact that  these  word formation processes could help develop morphological rules that can be used for developing computational morphological tools like- stemmer, spell checker, tagger etc.


Introduction
It is assumed that the origin of the Assamese language is from the Magadhan group of the Indo-Aryan language family. G. C. Goswami (1982) states: "It is supposed that like other Aryan languages, Assamese was also born from Apabhramsa dialect developed from Magadhi Prakrit of the eastern group of Sanskrit language". Trask (1999: 47) defines derivation as a way of constructing new words by adding affixes to existing words. Derivation is one of the basic ways of obtaining new words in most languages. According to Booij (2012:51) derivational process enables the users of a language to create new lexemes. Payne (2006:38) explains derivation in its difference from inflection which is another major word formation process. Derivation is best explained in its difference form inflection which is another major branch of morphology. Inflection is a word formation process that helps us to get grammatically distinct form of the same word. On the other hand derivation helps us to get new words. For example the inflected forms of the word write-writes, writing, written are only grammatically distinct form of the same word. On the other hand writer is a new word obtained with derivation from the word write. Inflectional affixes add grammatical information to the root, but derivational affixes contribute meaning to the root. Haspelmath and Sims (2010:86-89) listed common derivational meanings of word categories using terms like deverbal noun, deadjectival noun, denominal verb, deverbal adjective etc.

Derivation
Derivation is closely linked with the notion of lexicon in Anderson (1995: 180-184). Lexicon here is not analogous to a dictionary or a kind of list or database. It is the knowledge a speaker has of how words can interpret positions in a syntactic structure. As part of the lexicon this knowledge forms derivational rules. The function of these rules is to establish relation among stems to create new lexical stems on the basis of the existing one when required. Anderson further defines derivation as a class of word formation rules within the lexicon. These rules contain information about the lexical category, syntactic sub-categorization, semantics and argument structure, etc. of the stems to which they apply. Thus, there is not much difference between inflectional and derivational word formation rules. But there is a core difference between both of them. Inflection brings structural changes affecting the phonological form of the word. On the other hand derivation results in the semantic as well as syntactic modification of a word. Derivational pattern in languages can be broadly understood from the schema in Fig. 1.

Derivation of Assamese Nouns
Creating new words for new concepts is one of the chief functions of derivational morphology. We also have a greater need for naming diverse nominal concepts; this explains why languages generally have more means for deriving nouns than for deriving verbs and adjectives (Haspelmath and Sims 2010: 87). In Assamese, both prefixes and suffixes are used to derive nouns. Use of prefix to derive nouns in Assamese is shown in Table 1.
From Table 1 it can be seen that the prefixes in the table have both negative as well as positive connotation. xɔmɔi, pɔl and kɑl are synonyms i.e. different words with same meaning. However, the difference in their usage is shown in (1).
ho-i xɔmɔi pɑɹ hɔi time fraction of time be-NF time pass be 'Time passes in fraction.' From (1a-d) it can be seen that although the meaning of both xɔmɔi, kɑl and pɔl are same the derived nouns ɔxɔmɔi, ɑkɑl and ɔnupɔl have different connotation. ɔxɔmɔi means 'wrong time' ɑkɑl means 'famine' and ɔnupɔl means 'fraction of time'. (1.a) shows that ɔxɔmɔi is not followed by any other bound morpheme. But in (1.b) ɔxɔmɔi is followed by the locative case marker -t.  Crystal (2008:141) defines de-verbal noun as noun that originates as a verb but used as noun in sentence structure. Deverbal noun in Assamese is shown in Table 2.  Table 2 shows how the derivational suffixes -ɔni, -uoi, -ɔɹiɑ, -ʊtɑ and -jɔk/ɔk derive nouns from a verb.

(a) nɑs-ɔni-ɛ bihu nɑs
The dancer is dancing Bihu dance.' 'The players came.' In (2a) and (2b) the verbs nɑs 'dance' and k h ɛl 'play' are nominalised by the suffixes -ɔni and -uoi and the derived nominals can function like pure nouns. The derived nominals which occur in the subject position in (2ab) takes the ergative case marker -ɛ in nɑsɔniɛ (2a) and in (2b) k h ɛluoi takes the collective suffix -xɔkɔl to indicate that it patterns like regular nouns. In (2a) the subject is an 'agent' i.e. doer of an action and in (2b) the subject is a 'theme' to which the reference is made.

Deadjectival noun (A→ N)
De-adjectival noun involves derivation of a noun from an adjective and Crystal (2008:130) defines it as noun that originates as an adjective but used as noun in sentence structure. Table 3 shows deadjectival nouns in Assamese. Indian J. Lang. Linguist., 1(2) (2020), 1-15 | 5 tea assam-GEN one special-DNOM be 'Tea is a specialty of Assam.' The derived deadjectival noun takes plural marker and classifier as shown in (4a-b).

(a) bɛjɑ-bʊɹ
'You take the good ones.' (4a-b) shows derivation of nouns from adjectives in Assamese. In (4a) the plural marker -bʊɹ is suffixed to the adjective bɛjɑ 'bad' to derive noun. In (4b) the quantifier -k h ini is suffixed to the adjective to derive the object noun b h ɑlk h ini. The derived nouns bɛjɑbʊɹ and b h ɑlk h ini function as direct object of verb in the sentence structure.
From (3) and (4) we find two types of deadjectival nouns: those in Table 3 which take suffixes like -ɔtɑ,twɔ etc. and those which do not take a derivational suffix as in (4a-b). But in both (3) and (4) the derived nouns function as nouns. niɹɔbɔtɑ and bixɛxɔtwɔ in (3a-b) are nouns derived from adjectives and function as nouns in sentence structure. Similarly, tɛ ŋɑbʊɹ (4a) and kolɑ-tʊ (4b) can be considered as noun as they sit in the subject and object position in the sentences without taking a derivational suffix.

De-nominal nouns (N→ N)
De-nominal nouns are nouns derived from another noun. Derivation of denominal nouns in Assamese is shown in Table 4.  Table 4 shows derivation of nouns from nouns in Assamese with the help of suffixes -kɑɹ, -ikɔɹɔn/kɔɹɔn, -b h ɔwɔn, -ɔɹiɑ, -ɔtwɔ/twɔ. From the table it can be seen that the derived nouns are different from the source noun in meaning. For example, suffixation of -kɑɹ to the noun gɔlpɔ 'story' derives the noun gɔlpɔkɑɹ 'story writer'. Suffixation of -ikɔɹɔn to the noun gʊlɔk 'globe' derives another noun gʊlɔkikɔɹɔn 'globalization', -ikɔɹɔn has an allomorph -kɔɹɔn. When the morpheme -b h ɔwɔn is suffixed to nouns like bɑspɔ 'steam' it derives the noun bɑspɔib h ɔwɔn'act of converting liquid to steam'. The morphophonemic change /ɔ/→/i/ can be seen as a result of this suffixation. When the morpheme -ɔɹiɑ is suffixed to the noun nɑʊ̃ 'boat' it derives the noun nɑwɔɹiɑ 'boatman'. Suffixation of the morpheme -ɔɹiɑ to nɑʊ̃ triggers the morphophonemic change /ʊ/→/w/.Similarly the suffix -twɔ derives the noun bjɔktitwɔ 'personality' from the noun bjɔkti 'person'. -twɔ is one of such suffixes DOI: 10.34256/ijll2021 Indian J. Lang. Linguist., 1(2) (2020), 1-15 | 6 which can be used to derive words from more than one word categories. -twɔ has an allomorph -ɔtwɔ which derives nɑgɔɹikɔtwɔ from nɑgɔɹik. -twɔ can derive noun from adjective (Table 3) and noun form noun (Table  4). The examples in (5a-b) show some denominal nouns in the subject position of the declarative clauses.

De-nominal nouns with negative connotation
Bound morphemes ɔ-, duɹ-and du-derive nouns which have negative connotation as shown in Table5, 6 and 7. These bound morphemes are prefixes and they are class maintaining prefixes. Table 5 shows derivation of denominal nouns with the help of the prefix ɔ-, followed by Tables 6 and 7 with the duɹ-and du-prefixes respectively.

Derivation of Assamese Verbs
In Assamese verbs can be derived both by prefixation and suffixation. In the sections to follow we will look into the derivation of verbs in the language. Crystal (2008: 135) defines de-nominal verb as verb that originates as a noun but used as verb in sentence structures. De-nominal verb formation is not very productive in Assamese.
In (6)  The sentences in (6) show derivation of a verb from a noun with the derivational suffix --ijɑ /-jɑ. In (6a) the derivational suffix -ijɑ derives the verb g h usijɑ 'hit with fist' from the noun g h usɑ 'fist'. The back open vowel /ɑ/ of the second syllable in g h usɑ is dropped and the deverbal morpheme -ijɑ is suffixed to derive the verb g h usijɑ. In (6b) the derivational suffix -jɑ which is an allomorph of -ijɑ, follows the noun p h ɔni 'comb' to derive the verb p h ɔnijɑ. -jɑ is followed by the conjunctive participle -i to form the compound verb p h ɔni-jɑ-i lʊɑ ' comb' which includes the tense and agreement features Barbora (2001:101) states that negatives in Assamese are bound morphemes. The bound morpheme nprefixes to a root verb and copies its vowel as shown in Table 9.  Table 9 shows derivation of verbs with the help of negative morpheme n-. Barbora (2001:101) explains in detail that negative prefix n-copies the vowel of the root word. In (7a-b)  Indian J. Lang. Linguist., 1(2) (2020), 1-15 | 8 (b) rɑm-ɛ b h ɑl-koi nɔ-pɔɹh-ɛ ram-NOM good-DADV NEG-read-3 'Ram does not study properly.'

Deverbal verbs (Negative verbs)
(7a-b) shows derivation of negative verbs in Assamese. In (7a) the derivational morpheme n-is prefixed to the verb k h ɑ to derive the negative verb nɑk h ɑ. Here the negative morpheme is n. n takes /ɑ/ as a result of vowel copying from the verb root k h ɑ. In (7b) the derivational morpheme n-is prefixed to the verb pɔɹh to derive the negative verb nɔpɔɹh. Here also we see instance of vowel copying when the negative morpheme n-copies the vowel /ɔ/ from pɔɹh.

De-adjectival verb
De-adjectival verb is an instance of derivation of a verb from an adjective. Crystal (2008: 130) defines deadjectival verb as a verb that originates as an adjective but used as verb in sentence structure. In Assamese there are some adjectives which sit in the position of a verb without taking any derivational suffix. However, when they sit in the position of a verb, they take inflectional morphemes like causative, tense, aspect and person markers as shown in (8a-b).

Derivation of Assamese adjectives
Derivation of adjectives in Assamese is a very productive process. In Assamese adjectives are derived from noun, adjective and verb.

De-nominal adjective
Denominal adjectives are adjectives derived from a base noun. Crystal (2008: 135) defines denominal adjective as adjective that originates as a noun but used as an adjective in a sentence. In Assamese adjectives are formed from nouns by the following class changing derivational suffixes as shown in (9). (9a-d) shows how adjectives are derived from nouns in Assamese. In (9a) the noun kɔlpɔnɑ 'imagination' is suffixed with the derivational suffix -ik to derive the adjective kɑlpɔnik 'imaginary'. Derivation of the word kɑlpɔnik from kɔlpɔnɑ shows morphophonemic change where the where the back vowel between close and half close changes to a back open vowel tat is, /ɔ/→/ɑ/. The word final ɑ of kɔlpɔnɑ is dropped before suffixing -ik. In (9b) the adjective ɹɑstɹijɔ 'national' is derived from the noun ɹɑstɹɔ 'nation'. Here, when the derivational morpheme -ijɔ is suffixed to the noun ɹɑstɹɔ vowel dropping takes place as a result of which the word final /ɔ/ of ɹɑstɹɔ is dropped before suffixing -ijɔ. The derivational suffix -mulɔk that derives the adjective in (9c) is a typical bound morpheme that is actually derived from a noun mul 'root' by suffixing the -ɔk morpheme. However,mulɔk is a bound morpheme that derives an adjective from a noun sɹisti 'creation' in (9c). (9d) gives an instance of a derivational prefix ɔ-that derives the adjective ɔmuljɔ 'priceless' from a noun muljɔ 'price'.

De-nominal adjective with negative connotation
When bound morphemes ni-, niɹ-and -hin are affixed to a noun they derive adjectives and the derived adjectives give the sense of 'devoid of / without something that is referred by the noun'. These are shown with examples in Table 10, 11 and 12.

De-verbal adjectives
As the name suggests, de-verbal adjectives are adjectives realized through derivational process by suffixing a derivational morpheme to a verb. In Table 13, we have instances of derivation of adjectives from verbs.  Table 13 shows derivation of adjectives from verbs in Assamese with the suffixes -itɔ, -uɹɑ, ɔɹiɑ. Suffixation of -itɔ derives adjective ɹɔsitɔ 'composed' from the verb ɹɔs 'compose'. Suffixation of the derivational suffix -uɹɑ to the verb kɑnd 'cry' derives the adjective kɑnduɹɑ 'cry baby'. Suffixation of -ɔɹiɑ to the verb pɔlɑ 'flee' derives the adjective pɔlɔɹiɑ 'one who flees'. This derivation in Assamese is shown in examples (10a-d). 'The girl is a crybaby.' In (10a) and (10b) the derivational suffix -itɔ derives an adjective from a verbs lik h 'write' and rɔs 'compose'. Derivational suffix -uɹɑ derives an adjective kɑndʊɹɑ 'a boy who is a crybaby' from a verb kɑnd 'cry' in (10c). The feminine counterpart of -uɹɑ is -ʊɹi which derives kɑndʊɹi 'a girl who is a crybaby' from the verb kɑnd 'cry' in (10d).

De-adjectival adjective
De-adjectival adjectives are adjectives derived from adjectives. Affixation of a bound morpheme with adjective changes the meaning of the root adjective and in this process derives another adjective which is shown in Table 14: Table 14 shows derivation of adjectives from adjectives in Assamese with the prefix -ɔ. The prefix ɔderives adjectives like ɔxɔb h jɔ 'uncivilised', ɔzuktikɔɹ 'unreasonable' ɔxɑd h ɑɹ ɔn 'extraordinary' and ɔtulɔniɔ 'incomparable' from another adjective xɔb h jɔ 'civilized', zuktikɔɹ 'reasonable' xɑd h ɑɹɔn 'ordinary' and tulɔniɔ 'comparable' respectively. Thus ɔ-is a class maintaining derivational prefix. Thus we can see that prefix ɔ-derives an adjective having a negative meaning as well as positive meaning.

DOI: 10.34256/ijll2021
Indian J. Lang. Linguist., 1(2) (2020), 1-15 | 11 From the above analysis it is evident that ɔ-is a very productive derivational morpheme that derives adjective from adjective (see Table 15) and noun form noun (see Table 1). This prefix is more productive in deriving an adjective from another adjective.

Derivation of Assamese Adverbs
Adverbs in Assamese are derived from word categories like noun and adjective by affixing derivational morphemes. In Table 16 we have instances of derived adverbs from nouns:

Denominal Adverbs
Denominal adverb is an adverb derived from a noun. Derivation of an adverb from noun is very frequent in Assamese. Morphemes -rɛ,and -ɑi are suffixed with a noun to derive an adverb from a noun which is shown in Table 15. Indian J. Lang. Linguist., 1(2) (2020), 1-15 | 12 The morpheme -ɑi can be directly suffixed to the noun to derive an adverb as in (12a). But (12b) shows that the morpheme -dɔɹɛ cannot be suffixed directly to the stem. The genitive morpheme -ɹ is suffixed first with the noun stem which is followed by the derivational suffix -dɔɹɛ. Following Crystal (2008:130) de-adjectival adverb can be explained as an adverb that originates as an adjectival but can be used as an adverb in a sentence. De-adjectival adverbs is formed with the derivational suffixes -koi and -ɑi. These two bound forms are very productive in the language  Table 16 shows derivation of adverbs from adjectives in Assamese with the suffixes -koi, and -ɑi. Suffixation of -koi to the adjectives sizil 'neat' and k h ɔɹ 'fast' derives the adverbs sizilkoi 'neatly' and k h ɔɹkoi'speedily'respectively. Suffixation of -ɑi to adjectives g h ɔn 'dense/frequent'and bɔhɔl 'broad/wide' derives adverbs g h ɔnɑi 'densely/frequently' and bɔhɔlɑi 'broadly' respectively. In (13a-c) we have sentences where the adverbs derived by -koi and -ɑi function as adverb of manner.

Complete reduplication
In Table 17 we have a few examples of complete repudlication in Assamese. The suffix -ɛ adjoins to the adjective and the reduplicated form functions as an adjective

Denominal adverbs
In Table 18, we have instances of derivation of manner adverbs from nouns. Here too the adverbial marker -koi and the reduplicated marker -ɛ suffixes to the noun to derive adverbs.
The adverbial marker -koi suffixes to the noun xɑɹi 'row' to derive the adverb xɑɹikoi ' in a row'. The suffix -ɛ derives the adverb kɑnɛ kɑnɛ 'silently whisper in the ear' from the noun kɑn 'ear'. In (14a-b) the derived adverbs modify the main verbs. 14.
Morphophonemic change of the stem is observed in cases like nɑwɔɹiɑ 'boatman', when the bound morpheme -ɔɹiɑ is suffixed to nɑʊ̃ 'boat' here we observe morphophonemic change where /ʊ/→/w/. Also we have instances of vowel copying when the negative morpheme n-is prefixed to a verb root. Also some allomorphs observed in our analysis are -ikɑɹ/kɑɹ, ikɔɹɔn/kɔɹɔn, -jɔk/ok, -ɔtwɔ/twɔ, -ijɑ/jɑ. Lastly we have observed some bound morphemes have the ability to affix with different word categories to derive new words. For example, -twɔ can derive noun from adjective and noun form noun.