A fast FORTRAN implementation of the U. S. naval research laboratory algorithm for automatic translation of english text to VOTRAX parameters

The U. S. Naval Research Laboratories algorithm of Elovitz et. al. enables automatic transalation of English text to IPA and, via a further mapping, to input for a "phoneme" based synthesizer such as VOTRAX. A novel feature of the NRL algorithm is that the set of 300+ rules used to perform the translation is read in at run time and thus may be easily altered to expand the set of rules in general or to treat special cases such as jargon. While the orignal NRL FASBOL version ran about 4 to 5 times real time on a PDP-10, Broihier and Crowley implelemented a BASIC Plus version which translated up to 165 words per minute on a PDP-11/70. The program included here consists essentially of a FORTRAN control structure with calls to string manipulation subroutines, available as efficient library routines under the PDP-11 RT-11 operating system. The software runs in less than real time on an LSI-11 with 16K of memory. Alternatively, using the string manipulation routine definitions provided, an all-FORTRAN version may be written. Finally, the straightforward, non-recursive structure employed can implemented in other high level languages. In fact, a PL/M version has been written which, using calls to assembler routines employing block move instructions, will run real time on a Zilog Z-80.