1 Some Empirical Aspects of Verb Inflection in Bulgarian and German James Kilbury Katina Bontcheva Computerlinguistik Computerlinguistik Institut für Sprache und Information Institut für Sprache und Information Heinrich-Heine-Universität Düsseldorf Heinrich-Heine-Universität Düsseldorf Universitätsstr. 1 Universitätsstr. 1 D-40225 Düsseldorf, Germany D-40225 Düsseldorf, Germany [email protected] [email protected] Keywords: inflectional morphology, non- framework of Paradigm Function Mor- monotonic inheritance, DATR, empirical phology (cf. Stump 2001). evidence, language acquisition, Bulgarian In the analyses presented here we treat verb inflection, German verb inflection, Bulgarian and German verb inflection in abstract morphophonemic representation terms of NM and closely related frame- works. Inflectional types are represented as Abstract objects within a nonmonotonic inheritance The paper discusses analyses of Bulgarian hierarchy that provides an explicit account and German verb inflection that are based of regularities, subregularities, and excep- on nonmonotonic inheritance and encoded tions with highly constrained lexical en- in DATR. The analysis of Bulgarian also tries, default inflectional classes, and non- makes essential use of abstract morpho- productive classes. We try to avoid as phonemic representations. We argue that much as possible the use of virtual classes such analyses of inflectional morphology that do not reflect any concrete inflectional must reflect and be supported by empirical type, and, for Bulgarian, we employ ab- data on language acquisition and mental stract morphophonemic representations to lexical representations reported in psycho- simplify the description of the alternations linguistic studies. and morphotactics (for details on our use of such representations cf. Bontcheva & Kil- 1 Introduction bury 2003). Our analyses are encoded in Since the mid 1980’s representation lan- DATR. guages based on networks with multiple and nonmonotonic inheritance have been 2 Empirical basis of NM analyses employed in descriptions of inflectional While monotonic classifications of inflec- morphology. Typically, nodes denote gen- tional types or other objects can be deter- eralized paradigms or inflectional classes, ministically computed (cf. Petersen 2004), while the relations between inflectional nonmonotonic classifications in principle classes are captured by the hierarchical re- allow arbitrary structuring and require ex- lations between nodes. In 1989 DATR (cf. ternal specification as to what counts as Evans & Gazdar 1996) was introduced as a regular or general. Thus, NM-based ac- formalism for lexical knowledge represen- counts of inflectional morphology must tation that avoids certain problems such as specify further formal criteria and/or em- conflicts of multiple inheritance. Since then pirical evidence for particular analyses. it has become widely adopted in computa- Early accounts of NM and other tional linguistics. DATR-oriented work tended to neglect the Network Morphology (NM) utilizes empirical criteria for particular proposals DATR notation and principles of inheri- involving class hierarchies (cf. Corbett & tance networks in a linguistic theory of in- Fraser 1993), but recent studies seek to flectional morphology (cf. Corbett & Fraser provide empirical justification through cor- 1993, Corbett 2000). NM reflects a grow- pus investigation of frequencies (cf. Brown ing theoretical linguistic interest in inheri- et al. 2004). In particular, psycholinguistic tance-based morphology and is close to the data on first language acquisition has been advanced to support hierarchical analyses 2 of German noun inflection (cf. Cahill & never have a form like *muhl in analogy to Gazdar 1999, Clahsen et al. 2002). fuhr from fahren (Vaba). In this paper we couple psycholinguis- For geschrieben we expect the forms tic criteria with formal constraints on hier- *geschreiben (Vn/Vaba) and geschreibt archies in NM accounts of inflectional (V), but rufen would not have a form like classes: *geriefen (Vabb) in analogy to geschrieben • In accord with the studies on German from schreiben. mentioned above we require that im- Finally, beside gesungen the analysis mediate dominance (ID) relations be- predicts the three forms *gesangen (Vabb), tween nodes for inflectional classes *gesingen (Vn/ Vaba), and *gesingt (V). mirror the direction of overgeneraliza- All the predictions ultimately should be tion in language acquisition. confirmed in order to support the analysis. • Moreover, we extend the previous If only the form *gesingt is in fact attested, principle to the transitive closure of the then this would speak against the specific ID relation. hierarchical structuring proposed here. • Finally, we assume that overgeneraliza- Note also that our analysis excludes tion invariably involves analogy to a any paradigm not found in a real inflec- concrete inflectional type, which means tional type (e.g., rufen – rief – *geruft) and that hierarchies should include no accordingly involves no corresponding nodes for virtual classes not repre- nodes for virtual classes. This restriction is sented by real lexemes. fulfilled but not explicitly discussed in some recent descriptions of German noun The principles can be illustrated with a part inflection (cf. Cahill & Gazdar 1999, Kil- of our analysis of German verb inflection. bury 2001). We assume a linear ordering of nodes for Further details of this analysis and the the following classes with V as root: empirical evidence will be presented in an- • V for lachen ‘laugh’ other study. We break off the discussion • Vn for mahlen ‘grind’ here and go on to a parallel investigation of • Vaba for rufen ‘call’ Bulgarian morphology. • Vabb for schreiben ‘write’ • Vabc for singen ‘sing’. 3 Bulgarian verb inflection V is the regular inflection with preterite In this paper we describe the construction stem in –te (lachte) and perfect participle in of the synthetic forms that involve only –t (gelacht). Vn inherits everything from V inflection, i.e., the forms for present, aorist, except the form of the participle, which is and imperfect tense, the participles (present built with –n (gemahlen). active, aorist, imperfect, past passive), the Vaba introduces a distinct stem vowel verbal noun and adverb, and the simple in the preterite stem (rufen – rief – forms for imperative. gerufen), while Vabb has the same distinct Most Bulgarian verbs have forms for vowel in both preterite and the participle both perfective and imperfective aspect (schreiben – schrieb – geschrieben). Fi- although some verbs are imperfectiva tan- nally, Vabc introduces three distinct vowels tum, i.e., without a form for perfective as- (singen – sang – gesungen). pect. Quite often these forms have different Our hierarchy makes very explicit em- aspectual stems and belong to different pirical predictions that should be confirmed conjugations. Also, the perfective and the or refuted by psycholinguistic data. Over- imperfective stems take different sets of generalizations in language acquisition are nonfinite inflections. For this reason, al- invariably directed upward in the hierarchy, though they are forms of one and the same so that we find *gemahlt but never lexeme, the perfective and the imperfective *gelachen in data from children (cf. stems appear here as independent entries. Clahsen et al 2002). Traditionally, one speaks of three con- For the preterite rief from rufen we ex- jugations in Bulgarian. Two of them repre- pect regular *rufte (V), but mahlen should sent old inflectional types, inherited from Old Church Slavonic. They have numerous classes and even subclasses defined by the 3 relationship between the present-tense stem There are seven inflectional classes that and the aorist stem. Actually, these conju- belong to the 1st (e) conjugation and two to gations are virtual – no verb is defined as the 2nd (i) conjugation. Here the class- belonging to the 1st or 2nd conjugation specific features are stored that constitute without additional reference to the inflec- subregular exceptions to the defaults de- tional class. The third conjugation is new scribed in Va. Most classes have subclasses and emerged as the process of secondary with regard to stress and the type of base imperfectivization with the suffixes -а-(-я-) (i.e., vocalic or consonant). /-ва-/-ава-(-ява-)/-ува- became very pro- All lower nodes by default inherit the ductive. In contrast to the 1st and 2nd conju- features from higher nodes in the hierarchy. gations, it is not virtual and has no classes. However, the inheritance is nonmonotonic The verbs belonging to the 1st and 2nd and at each level the information inherited conjugations have two basic stems tradi- by default can be overridden (cf. the code tionally called present-tense stem and the below). aorist (infinitive) stem. The verbs that be- Bulgarian verbs have two aspectual long to the 3rd conjugation have only one stems described in different entries (cf. stem, which has no thematic vowel and is above). Each imperfective or perfective equal to the base (i.e., the aspectual stem). stem2 adds a set of inflectional elements The present-tense stem is used in the such as: following forms: present tense, imperfect tense, the simple forms for imperative, pre- • stem vowels for the temporal stems (sv sent active participle, imperfect participle, $tens, i.e., stem vowels for present, ao- and the verbal adverb. Actually, it is the rist, imperfect tense) imperfect-tense stem