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Riva TTS English Normalization Grammar

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Base English grammar



Latest Version



May 20, 2022


2.28 MB

Text Normalization: Weighted Finite State Transducer

Model Overview

This model is an OpenFST finite state archive (.far) for use within the opensource Sparrowhawk normalization engine [2]. This model has been created for English (en-US) text.

Model Architecture

This model uses weighted finite-state transducer (WFST) grammars that map strings in written form to strings in spoken form.


The model was constructed using Nemo toolkit as outlined in intro and Text processing

How to Use this Model

To use this model , we can use Riva Skills Quick start guide , it is a starting point to try out Riva models . Information regarding Quick start guide can be found : here.


This model is part of a pipeline for text to speech and accepts text as input.


The output is normalized text which is then passed to the next stage in the text to speech pipeline.


[1] NeMo Inverse Text Normalization: From Development To Production

[2] [Google Sparrowhawk] (


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