Speech systems are sensitive to accent variations. This is especially
challenging in the Indian context, with an abundance of languages but a dearth
of linguistic studies characterising pronunciation variations. The growing
number of L2 English speakers in India reinforces the need to study accents and
L1-L2 interactions. We investigate the accents of Indian English (IE) speakers
and report in detail our observations, both specific and common to all regions.
In particular, we observe the phonemic variations and phonotactics occurring in
the speakers' native languages and apply this to their English pronunciations.
We demonstrate the influence of 18 Indian languages on IE by comparing the
native language pronunciations with IE pronunciations obtained jointly from
existing literature studies and phonetically annotated speech of 80 speakers.
Consequently, we are able to validate the intuitions of Indian language
influences on IE pronunciations by justifying pronunciation rules from the
perspective of Indian language phonology. We obtain a comprehensive description
in terms of universal and region-specific characteristics of IE, which
facilitates accent conversion and adaptation of existing ASR and TTS systems to
different Indian accents.

研究印度英语说话者的口音，包括其母语语音的影响，并系统性地描述了印度英语的特点，以便于在自动语音识别和语音合成系统中实现印度口音的转换和适应。

印度本土语音素对 L2 英语发音影响的研究

An Investigation of Indian Native Language Phonemic Influences on L2 English Pronunciations

Analysis of Indian English (IE) pronunciation variabilities are useful in
building systems for Automatic Speech Recognition (ASR) and Text-to-Speech
(TTS) synthesis in the Indian context. Typically, these pronunciation
variabilities have been explored by comparing IE pronunciation with Received
Pronunciation (RP). However, to explore these variabilities, it is required to
have labelled pronunciation data at the phonetic level, which is scarce for IE.
Moreover, versatility of IE stems from the influence of a large diversity of
the speakers' mother tongues and demographic region differences. Prior
linguistic works have characterised features of IE variabilities qualitatively
by reporting phonetic rules that represent such variations relative to RP. The
qualitative descriptions often lack quantitative descriptors and data-driven
analysis of diverse IE pronunciation data to characterise IE on the phonetic
level. To address these issues, in this work, we consider a corpus, Indic
TIMIT, containing a large set of IE varieties from 80 speakers from various
regions of India. We present an analysis to obtain the new set of phonetic
rules representing IE pronunciation variabilities relative to RP in a
data-driven manner. We do this using 15,974 phonetic transcriptions, of which
13,632 were obtained manually in addition to those part of the corpus.
Furthermore, we validate the rules obtained from the analysis against the
existing phonetic rules to identify the relevance of the obtained phonetic
rules and test the efficacy of Grapheme-to-Phoneme (G2P) conversion developed
based on the obtained rules considering Phoneme Error Rate (PER) as the metric
for performance.

本文从语音识别和语音合成的角度出发，对印度英语的发音变异进行了分析和研究，提出了一种基于数据驱动的新型语音转换模型，并用基于音素错误率的性能指标进行了测试。