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The following paper is available in compressed postscript form by anonymous ftp from the Indiana University Computer Science Department ftp archive (instructions below). The paper is 60 pages long. Hardcopies are not yet available, maybe in the fall. Comments welcome. Michael Gasser gasserMail to author|Respond to list|Read more issues|LINGUIST home page|Top of issuecs.indiana.edu ================================================================= Learning Words in Time: Towards a Modular Connectionist Account of the Acquisition of Receptive Morphology Michael Gasser Computer Science and Linguistics Departments Indiana University To have learned the morphology of a natural language is to have the capacity both to recognize and to produce words consisting of novel combinations of familiar morphemes. Most recent work on the acquisition of morphology takes the perspective of production, but it is receptive morphology which comes first in the child. This paper presents a connectionist model of the acquisition of the capacity to recognize morphologically complex words. The model takes sequences of phonetic segments as inputs and maps them onto output units representing the meanings of lexical and grammatical morphemes. It consists of a simple recurrent network with separate hidden-layer modules for the tasks of recognizing the root and the grammatical morphemes of the input word. Experiments with artificial language stimuli demonstrate that the model generalizes to novel words for morphological rules of all but one of the major types found in natural languages and that a version of the network with unassigned hidden-layer modules can learn to assign them to the output recognition tasks in an efficient manner. I also argue that for rules involving reduplication, that is, the copying of portions of a root, the network requires separate recurrent subnetworks for sequences of larger units such as syllables. The network can learn to develop its own syllable representations which not only support the recognition of reduplication but also provide the basis for learning to produce, as well as recognize, morphologically complex words. The model makes many detailed predictions about the learning difficulty of particular morphological rules. ************************************************ INSTRUCTIONS FOR ELECTRONIC RETRIEVAL VIA ANONYMOUS FTP unix> ftp cs.indiana.edu # or ftp 129.79.254.191 Connected to cs.indiana.edu. 220 moose FTP server (Version 2.0WU(11) Tue Apr 20 16:27:56 EST 1993) ready. Name (cs.indiana.edu:gasser): anonymous 331 Guest login ok, send your complete e-mail address as password. Password: <your-email-address> 230-Welcome, archive user! This is an experimental FTP server. If have any 230-unusual problems, please report them via e-mail to root
moose 230-If you do have problems, please try using a dash (-) as the first character 230-of your password -- this will turn off the continuation messages that may 230-be confusing your ftp client. 230- 230 Guest login ok, access restrictions apply. ftp> cd pub/techreports 250 CWD command successful. ftp> binary 200 Type set to I. ftp> get TR384.ps.Z 200 PORT command successful. 150 Opening BINARY mode data connection for TR384.ps.Z (311529 bytes). 226 Transfer complete. local: TR384.ps.Z remote: TR384.ps.Z 311529 bytes received in 2.2 seconds (1.4e+02 Kbytes/s) ftp> quit 221 Goodbye. unix> uncompress TR384.ps.Z unix> lpr TR384.ps # or however you print PostScript files