Consonant Spreading in Arabic Stems

Consonant Spreading in Arabic Stems Kenneth R. BEESLEY Xerox Research Centre Europe Grenoble Laboratory 6, chemin de Maupertuis 38240 MEYLAN ]~¥aIICO Ken. Beesley@xrce. xerox, com Abstract ']'his paper examines the phenomenon of conso- nant spreading in Arabic stems. Each spread- ing involves a local surface copying of an un- derlying consonant, and, in certain phonologi~ cal contexts, spreading alternates productively with consonant lengthening (or gemination). The mOrl)hophonemic triggers of spreading lit in the patterns or even in the roots themselves, and the combination of a spreading root and a spreading pattern causes a consonant to be coiffed mulliple times. The interdigitation of Arabic stems and the realization of consonant spreading are forlnalized using finite-state roof photactics and variation rules, and this al> preach has been successfully implemented in a large-scale Arabic morphological analyzer which is available for testing on the Internet. 1 introduction Most formal analyses of Semitic languages, in- cluding Arabic. deDnd the reality of abstract, unpronounceable morphemes called ROOTS, consisting usually of three, but soinetimes two or four, consonants called RADICALS. The clas- sic examples include ktb (~. CJ '2) 1, al)pearing ill a number of words having to do with writ- ing, books, schools, etc.; and drs (~r' o z), ap- pearing in words having to do with studying, learning, teaching, etc. Roots combine non- concatenatively with t'ATTI,;flNS to form STt,;MS, a process known informally as INTERDIGITA- ?'ION or 1NTBRCALATION. We shall look first at Arabic stems in general before examining GEMINATION and SPREADING, related phenom- ena wherein a single underlying radical is real- l"l'he Arabic-script examples in this paper were pro- duced using the ArabTeX package for ],~GX and DTEX by Prof. I)r. l(laus i, agally of the University of Stuttgart. daras duris darras duruus diraasa(t) darraas madrasa(t) madaaris lnadrasiyy tadriis 'study' 'be studied' 'teach' 'lessons' 'study' 'eager student' 'school' 'schools' 'scholastic' 'instruction' ve r I) verb verb noulI. noun Boun nottn ROllS adj-like sou n Figure 1: Some stems built on root drs ized multiple times in a surface string. Semilic morphology, including stem interdigitation and spreading, is adequately and elegantly fornializ- able using finite-state rules and operations. 1.1 Arabic Stems The stems in Figure 12 share the drs root mor- pheme, and indeed they are traditionally ol:- ganized under a drs heading in printed lexi- cons like the authoritative Dictionary of Alod- ern Written Arabic of Hans Wehr (197!)). A root morpheme like drs interdigitales with a pattern morpheme, or, in some analyses. with a pattern and a separate vocalization [nor- pheme, to form abstract stems. Because inter- digitation involves pattern elements being in- serted between the radicals of the root mor- pheme, Semitic stem formation is a classic example of n on-concatenative inorphotactics. Separating and identifying the component mor- phemes of words is of course the core task of morphological analysis for any language, and analyzing Semitic stems is a classic challenge ~The taa] ) marbuuta, notated here as (t), is lhe fem- inine ending pronounced only in certain environments. Long consonants and …

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