This study investigates new-word formation devices in Modern Hebrew, focusing on those devices which seem to be more productive than others. It links together a number of processes which superficially seem unrelated, thereby providing an explanation to the question of productivity. We classify Modern Hebrew new-word formation processes into the following: (i) Non-linear Processes -Root & Pattern Affixation and Acronym Formation; (ii) Linear Processes including Linear Affixation and Backformation; Blending and Clipping; (iii) Zero Conversion. The central claim of this paper, expressed in the Structure Constraint, is that internal structure is a main factor in Modern Hebrew morphological typology and a direct cause of productivity: Structure-preserving devices manifest "natural productivity" and are used by all Speakers, whereas structure-violating ones are less productive and are likely to be employed in a deliberate manner by mature sophisticated Speakers to the exclusion of children and less well-educated Hebrew Speakers. The structure claim is examined in both child language and mature linguistic Systems. Hebrew and English, genetically nonrelated languages, are compared, demonstrating that the Structure Constraint (SO) is language-specific rather than universal. Folia Linguistica XXIV/3-4 0165-4004/90/24-289 $ 2-(C) Mouton/de Gruyter, Berlin -Societas Linguistica Europaea Brought to you by | University of Queensland -UQ Library Authenticated Download Date | 6/18/15 4:45 PM 290 1.0 IntroductionHebrew lexical items are known for their non-linear structure, exemplified in kesem 'magic', kosem 'magician', maksim 'charming', kasum 'charmed, magic', all sharing root q-s-m l (Berman 1969,1987, Gezenius 1910, Ravid 1978, Schwarzwald 1974. This paper focuses on a language-specific principle which derives from this fact, the Structure Constraint (SC), which requires that productive Modern Hebrew word-formation devices yield structured Output.The study analyzes 7 word-formation processes: Non-linear Affixation, Acronym Formation, Affix Concatenation, Backformation, Blending, Clipping and Zero-Conversion, in terms of the SC, demonstrating that internal structure is a main factor in Modern Hebrew morphological typology and a direct cause of productivity: Structure-preserving devices manifest "natural productivity" and are used by all Speakers, whereas structure-violating ones are less productive and are likely to be employed in a deliberate manner by mature sophisticated Speakers to the exclusion of children and less well-educated Hebrew Speakers.Hebrew forms are in broad phonemic transcription, with consonantal roots indicated by means of the historical elements attested in conventional orthography. Thus, for example, we use broad phonemic transcription for the verb kara 'tore', while its root is represented äs q-r-A, Standing for the historical Segments indicated by , and respectively. The voiceless palatal fricative is represented by 5; the voiced palatal fricative is represented by Z\ the voiceless ph...