Abstract
Plasticity of human speech production represents one of the greatest problems in speaker identification. During a criminal act, speakers may deliberately disguise their voice, and one of the disguise strategies is imitating an accent of a foreign language.
The main purpose of our research was to determine the characteristic features of imitated Russian accent in Czech. We recorded 10 male native Czech speakers reading a Czech text, "normally" (without any foreign accent) and while imitating a Russian accent.
To compare imitated and genuine Russian accent, we recorded 5 male Russian speakers reading the same text. Imitated Russian accent was analysed both acoustically and perceptually by comparing speakers' unmodified speech with imitation.
Goodness of imitation was assessed via an online perception test. All Czech speakers applied changes in word stress as the main tool in reproducing the Russian accent.
They lengthened stressed vowels and shifted stress to the second or third syllable in some words, and less frequently shortened or quantitatively reduced unstressed syllables. Half of the speakers modified pronunciation of [r̝/r̝] and [ɦ] occasionally, and instead produced [rʒ/rʃ] or [r] and [x] or [ɡ] respectively.
Only a few imitators managed to alter the pronunciation of high front vowels or of the lateral consonant. Measurement of suprasegmental parameters such as fundamental frequency range and articulation rate showed that all participants spoke more slowly during the imitation task and two of them increased their F0 range by more than 50%.
The perception test results show that 3 Czech imitators managed to produce a Russian accent that was believed to be authentic by most respondents, and 2 Russian speakers (with a weaker accent) were misclassified as imitators. All successful imitators are trained phoneticians, who are well familiar with Russian accent in Czech, and their accent was characterized by a greater number of deviations in pronunciation compared to other speakers.
None of the listeners identified the authenticity correctly for all speakers. Our further plan is a thorough comparison of the imitated and authentic Russian accent which could provide some criteria for distinguishing imitation from genuine accent.