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 France Ken. Beesley@xrce. xerox, com Abstract This 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 morphophonemic triggers of spreading lie 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 copied multiple times. The interdigitation of Arabic stems and the realization of consonant spreading are formalized using finite-state mor- photactics and variation rules, and this ap- proach 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, defend the reality of abstract, unpronounceable morphemes called ROOTS, consisting usually of three, but sometimes two or four. consonants called RADICALS. The clas- sic examples include ktb (~. ,D ~)1, appearing in a number of words having to do with writ- ing, books, schools, etc.; and drs (~9 z), ap- pearing in words having to do with studying, learning, teaching, etc. Roots combine non- concatenatively with PATTERNS to form STEMS, a process known informally as INTERDIGITA- TION or INTERCALATION. We shall look first at Arabic stems in general before examining GEMINATION and SPREADING, related phenom- ena wherein a single underlying radical is real- ~The Arabic-script examples in this paper were pro- duced using the ArabTeX package for TEX and DTEX by Prof. Dr. Klaus Lagally of the University of Stuttgart. daras duris darn'as duruus diraasa(t) darraas madrasa(t) madaaris madrasiyy tadriis 'study' 'be studied' 'teach' 'lessons' 'study' 'eager student' 'school' 'schools' 'scholastic' 'instruction' verb verb verb noun noun noun noun noun adj-like noun Figure 1: Some stems built on root drs ized multiple times in a surface string. Semitic morphology, including stem interdigitation and spreading, is adequately and elegantly formaliz- 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 or- ganized under a drs heading in printed lexi- cons like the authoritative Dictionary of Mod- ern Written Arabic of Hans Wehr (1979). A root morpheme like drs interdigitates with a pattern morpheme, or, in some analyses. with a pattern and a separate vocalization mor- 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 non-concatenative morphotactics. 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 2The taa~ marbuu.ta, notated here as (t), is the fem- inine ending pronounced only in certain environments. Long consonants and long vowels are indicated here with gemination. 117 …

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