Bohn is internationally recognized for his research on infant speech perception, cross-language speech perception, vowel perception, and second language speech.[8] Bohn's collaborations in these areas have resulted in the influential[9] Speech Learning Model and its revision,[10][11] in insights on infant, native, and cross-language vowel perception (with Winifred Strange and with Diane Kewley-Port), in the discovery of universal patterns of infant vowel perception (with Linda Polka), and in the study of cross-language perception of a range of consonants and vowels (with Catherine Best and with Terry Gottfried). Bohn is probably best known for his Desensitization Hypothesis[12] and for his work (with Linda Polka) on the Natural Referent Vowel framework.[13] His work on second language speech has provided support for the assumption that the capacity for phonetic category formation remains intact over the life-span. Address: Aarhus, Midtjylland, Denmark
Oxford Research Encyclopedia of Linguistics, Apr 26, 2018
The study of second language phonetics is concerned with three broad and overlapping research are... more The study of second language phonetics is concerned with three broad and overlapping research areas: the characteristics of second language speech production and perception, the consequences of perceiving and producing nonnative speech sounds with a foreign accent, and the causes and factors that shape second language phonetics. Second language learners and bilinguals typically produce and perceive the sounds of a nonnative language in ways that are different from native speakers. These deviations from native norms can be attributed largely, but not exclusively, to the phonetic system of the native language. Non-nativelike speech perception and production may have both social consequences (e.g., stereotyping) and linguistic–communicative consequences (e.g., reduced intelligibility). Research on second language phonetics over the past ca. 30 years has resulted in a fairly good understanding of causes of nonnative speech production and perception, and these insights have to a large extent been driven by tests of the predictions of models of second language speech learning and of cross-language speech perception. It is generally accepted that the characteristics of second language speech are predominantly due to how second language learners map the sounds of the nonnative to the native language. This mapping cannot be entirely predicted from theoretical or acoustic comparisons of the sound systems of the languages involved, but has to be determined empirically through tests of perceptual assimilation. The most influential learner factors which shape how a second language is perceived and produced are the age of learning and the amount and quality of exposure to the second language. A very important and far-reaching finding from research on second language phonetics is that age effects are not due to neurological maturation which could result in the attrition of phonetic learning ability, but to the way phonetic categories develop as a function of experience with surrounding sound systems.
Amsterdam studies in the theory and history of linguistic science, 2000
... It is therefore difficult to understand why Lucy (1997), in his review of research on linguis... more ... It is therefore difficult to understand why Lucy (1997), in his review of research on linguistic relativity, stated that" the neglect of em-pirical work is so conspicuous that it must be regarded as one of the central characteristics of this area of. research..."(1997: 294). ...
This chapter provides an overview of the main research questions and findings in the areas of sec... more This chapter provides an overview of the main research questions and findings in the areas of second language and cross-language speech perception research, and of the most widely used models that have guided this research. The overview is structured in a way that addresses three overarching topics in cross-language and second language speech perception research: The mapping issue (the perceptual relationship of sounds of the native and the nonnative language in the mind of the native listener and the L2 learner), the perceptual and learning difficulty/ease issue (how this relationship may or may not cause perceptual and learning difficulty), and the plasticity issue (whether and how experience with the nonnative language affects the perceptual organization of speech sounds in the mind of L2 learners). One important general conclusion from this research is that perceptual learning is possible at all ages but will be influenced by the entire language learning history of the individual. Introduction What happens when naïve listeners encounter the sounds of a foreign language for the first time, and what happens when native listeners learn an additional sound system in the course of second language acquisition? This chapter deals with cross-language speech perception (the naïve perception of the sounds of an unfamiliar language), and with the related dynamic that unfolds when the sound systems of the native language (L1) and a nonnative language (L2) 1 have to coexist in the mind of a second language learner.
Journal of the Acoustical Society of America, Jul 1, 1998
To examine the generality of Strange’s Dynamic Specification Theory of vowel perception, two perc... more To examine the generality of Strange’s Dynamic Specification Theory of vowel perception, two perceptual experiments investigated whether dynamic (time-varying) acoustic information about vowel gestures was critical for identification of coarticulated vowels in German, a language without diphthongization. The perception by native North German (NG) speakers of electronically modified /dVt/ syllables produced in carrier sentences was assessed using the “silent-center” paradigm. The relative efficacy of static target information, dynamic spectral information (defined over syllable onsets and offsets together), and intrinsic vowel length was investigated in listening conditions in which the centers (silent-center conditions) or the onsets and offsets (vowel-center conditions) of the syllables were silenced. Listeners correctly identified most vowels in silent-center syllables and in vowel-center stimuli when both conditions included information about intrinsic vowel length. When duration information was removed, errors increased significantly, but performance was relatively better for silent-center syllables than for vowel-center stimuli. Acoustical analyses of the effects of coarticulation on target formant frequencies, vocalic duration, and dynamic spectro-temporal patterns in the stimulus materials were performed to elucidate the nature of the dynamic spectral information. In comparison with vowels produced in citation form /hVt/ syllables by the same speaker, the coarticulated /dVt/ utterances showed considerable “target undershoot” of formant frequencies and reduced duration differences between tense and lax vowel pairs. This suggests that both static spectral cues and relative duration information for NG vowels may not remain perceptually distinctive in continuous speech. Analysis of formant movement within syllable nuclei corroborated descriptions of German vowels as monophthongal. However, an analysis of first formant temporal trajectories revealed distinct patterns for tense and lax vowels that could be used by listeners to disambiguate coarticulated NG vowels.
Journal of second language pronunciation, Sep 13, 2022
A large range of studies has generated predictions of second language (L2) speech learning proble... more A large range of studies has generated predictions of second language (L2) speech learning problems from perceptual assimilation patterns of nonnative sounds to native (L1) categories. The present study extends our knowledge of assimilation patterns as a predictor of L2 speech perception by examining the relationship between perceptual assimilation and L2 identification. Specifically, we examine how nonnative listeners’ perceptual assimilation of the full range of English initial consonants predicts their identification accuracy. Four groups of non-native listeners, differing orthogonally with regard to their L1 (Danish, Finnish) and English-language immersion experience (immersion, non-immersion) participated. As predicted, assimilation patterns interacted with L2 experience in accounting for how the L2 learners identified English consonants for some assimilation types, while the predictions were less successful for other assimilation types.
Journal of the Acoustical Society of America, Mar 1, 2018
James Jenkins had a keen interest in the nature of perceptual problems of nonnative listeners and... more James Jenkins had a keen interest in the nature of perceptual problems of nonnative listeners and in the perceived similarity of speech sounds. This presentation reports on a series of experiments which examined how well four different types of similarity predict nonnative speech perception. The different types are ecphoric and perceptual cross-language similarity, perceived within-language similarity, and acoustic similarity. One set of experiments examined how well cross-language perceptual assimilation (English to Danish) and within- language similarity ratings (English-English) of English consonants by Danish listeners predict Danes’ identification of English consonants. Another set of experiments explored the roots of English listeners’ discrimination problems for the closely spaced Danish unrounded front vowels by relating these problems to two types of perceived cross-language similarity (ecphoric and perceptual) and to acoustic similarity. Results suggest that each of the four types of similarity accounts for some of the perceptual problems, but none does so exhaustively, probably because the root system of these problems is affected by additional factors including nonnative listeners’ hypercorrection and by perceptual asymmetries. The clear conclusion from these experiments is that Jim’s question will keep us busy for quite some time. [Work supported by Carlsberg Foundation and Inge Lehmanns Legat af 1983.]
Journal of the Acoustical Society of America, Apr 1, 1996
This study investigated American English (AE) speakers’ perceptual assimilation of North German (... more This study investigated American English (AE) speakers’ perceptual assimilation of North German (NG) vowels spoken in 5 CVC contexts by four adult male speakers. Fourteen NG vowels were produced in /bVp, bVt, dVt, gVt, gVk/ syllables in the sentence ‘‘Ich habe CVC gesacht.’’ Twelve monolingual AE listeners were tested on each speaker’s corpus; consonantal context was a within-subjects variable. Response categories were indicated by /hVd/ key words and IPA symbols. Listeners responded by selecting the AE category containing the vowel most similar to the one in the utterance and rating its ‘‘goodness of fit.’’ The percentages of selection of the modal AE response category for each NG vowel ranged from 99% for /i/→/i/ (best fit) to 41% for /o//→/u/ (worst fit). NG front and back rounded vowels were assimilated to AE back rounded vowels. However, for seven vowels, modal category percentages differed by greater than 15% across the five consonantal contexts. There was also significant variation in assimilation patterns across the four speaker groups for 11 of the NG vowels. These results have implications for theories of L2 speech learning. [Work supported by NIDCD.]
Oxford Research Encyclopedia of Linguistics, Apr 26, 2018
The study of second language phonetics is concerned with three broad and overlapping research are... more The study of second language phonetics is concerned with three broad and overlapping research areas: the characteristics of second language speech production and perception, the consequences of perceiving and producing nonnative speech sounds with a foreign accent, and the causes and factors that shape second language phonetics. Second language learners and bilinguals typically produce and perceive the sounds of a nonnative language in ways that are different from native speakers. These deviations from native norms can be attributed largely, but not exclusively, to the phonetic system of the native language. Non-nativelike speech perception and production may have both social consequences (e.g., stereotyping) and linguistic–communicative consequences (e.g., reduced intelligibility). Research on second language phonetics over the past ca. 30 years has resulted in a fairly good understanding of causes of nonnative speech production and perception, and these insights have to a large extent been driven by tests of the predictions of models of second language speech learning and of cross-language speech perception. It is generally accepted that the characteristics of second language speech are predominantly due to how second language learners map the sounds of the nonnative to the native language. This mapping cannot be entirely predicted from theoretical or acoustic comparisons of the sound systems of the languages involved, but has to be determined empirically through tests of perceptual assimilation. The most influential learner factors which shape how a second language is perceived and produced are the age of learning and the amount and quality of exposure to the second language. A very important and far-reaching finding from research on second language phonetics is that age effects are not due to neurological maturation which could result in the attrition of phonetic learning ability, but to the way phonetic categories develop as a function of experience with surrounding sound systems.
Amsterdam studies in the theory and history of linguistic science, 2000
... It is therefore difficult to understand why Lucy (1997), in his review of research on linguis... more ... It is therefore difficult to understand why Lucy (1997), in his review of research on linguistic relativity, stated that" the neglect of em-pirical work is so conspicuous that it must be regarded as one of the central characteristics of this area of. research..."(1997: 294). ...
This chapter provides an overview of the main research questions and findings in the areas of sec... more This chapter provides an overview of the main research questions and findings in the areas of second language and cross-language speech perception research, and of the most widely used models that have guided this research. The overview is structured in a way that addresses three overarching topics in cross-language and second language speech perception research: The mapping issue (the perceptual relationship of sounds of the native and the nonnative language in the mind of the native listener and the L2 learner), the perceptual and learning difficulty/ease issue (how this relationship may or may not cause perceptual and learning difficulty), and the plasticity issue (whether and how experience with the nonnative language affects the perceptual organization of speech sounds in the mind of L2 learners). One important general conclusion from this research is that perceptual learning is possible at all ages but will be influenced by the entire language learning history of the individual. Introduction What happens when naïve listeners encounter the sounds of a foreign language for the first time, and what happens when native listeners learn an additional sound system in the course of second language acquisition? This chapter deals with cross-language speech perception (the naïve perception of the sounds of an unfamiliar language), and with the related dynamic that unfolds when the sound systems of the native language (L1) and a nonnative language (L2) 1 have to coexist in the mind of a second language learner.
Journal of the Acoustical Society of America, Jul 1, 1998
To examine the generality of Strange’s Dynamic Specification Theory of vowel perception, two perc... more To examine the generality of Strange’s Dynamic Specification Theory of vowel perception, two perceptual experiments investigated whether dynamic (time-varying) acoustic information about vowel gestures was critical for identification of coarticulated vowels in German, a language without diphthongization. The perception by native North German (NG) speakers of electronically modified /dVt/ syllables produced in carrier sentences was assessed using the “silent-center” paradigm. The relative efficacy of static target information, dynamic spectral information (defined over syllable onsets and offsets together), and intrinsic vowel length was investigated in listening conditions in which the centers (silent-center conditions) or the onsets and offsets (vowel-center conditions) of the syllables were silenced. Listeners correctly identified most vowels in silent-center syllables and in vowel-center stimuli when both conditions included information about intrinsic vowel length. When duration information was removed, errors increased significantly, but performance was relatively better for silent-center syllables than for vowel-center stimuli. Acoustical analyses of the effects of coarticulation on target formant frequencies, vocalic duration, and dynamic spectro-temporal patterns in the stimulus materials were performed to elucidate the nature of the dynamic spectral information. In comparison with vowels produced in citation form /hVt/ syllables by the same speaker, the coarticulated /dVt/ utterances showed considerable “target undershoot” of formant frequencies and reduced duration differences between tense and lax vowel pairs. This suggests that both static spectral cues and relative duration information for NG vowels may not remain perceptually distinctive in continuous speech. Analysis of formant movement within syllable nuclei corroborated descriptions of German vowels as monophthongal. However, an analysis of first formant temporal trajectories revealed distinct patterns for tense and lax vowels that could be used by listeners to disambiguate coarticulated NG vowels.
Journal of second language pronunciation, Sep 13, 2022
A large range of studies has generated predictions of second language (L2) speech learning proble... more A large range of studies has generated predictions of second language (L2) speech learning problems from perceptual assimilation patterns of nonnative sounds to native (L1) categories. The present study extends our knowledge of assimilation patterns as a predictor of L2 speech perception by examining the relationship between perceptual assimilation and L2 identification. Specifically, we examine how nonnative listeners’ perceptual assimilation of the full range of English initial consonants predicts their identification accuracy. Four groups of non-native listeners, differing orthogonally with regard to their L1 (Danish, Finnish) and English-language immersion experience (immersion, non-immersion) participated. As predicted, assimilation patterns interacted with L2 experience in accounting for how the L2 learners identified English consonants for some assimilation types, while the predictions were less successful for other assimilation types.
Journal of the Acoustical Society of America, Mar 1, 2018
James Jenkins had a keen interest in the nature of perceptual problems of nonnative listeners and... more James Jenkins had a keen interest in the nature of perceptual problems of nonnative listeners and in the perceived similarity of speech sounds. This presentation reports on a series of experiments which examined how well four different types of similarity predict nonnative speech perception. The different types are ecphoric and perceptual cross-language similarity, perceived within-language similarity, and acoustic similarity. One set of experiments examined how well cross-language perceptual assimilation (English to Danish) and within- language similarity ratings (English-English) of English consonants by Danish listeners predict Danes’ identification of English consonants. Another set of experiments explored the roots of English listeners’ discrimination problems for the closely spaced Danish unrounded front vowels by relating these problems to two types of perceived cross-language similarity (ecphoric and perceptual) and to acoustic similarity. Results suggest that each of the four types of similarity accounts for some of the perceptual problems, but none does so exhaustively, probably because the root system of these problems is affected by additional factors including nonnative listeners’ hypercorrection and by perceptual asymmetries. The clear conclusion from these experiments is that Jim’s question will keep us busy for quite some time. [Work supported by Carlsberg Foundation and Inge Lehmanns Legat af 1983.]
Journal of the Acoustical Society of America, Apr 1, 1996
This study investigated American English (AE) speakers’ perceptual assimilation of North German (... more This study investigated American English (AE) speakers’ perceptual assimilation of North German (NG) vowels spoken in 5 CVC contexts by four adult male speakers. Fourteen NG vowels were produced in /bVp, bVt, dVt, gVt, gVk/ syllables in the sentence ‘‘Ich habe CVC gesacht.’’ Twelve monolingual AE listeners were tested on each speaker’s corpus; consonantal context was a within-subjects variable. Response categories were indicated by /hVd/ key words and IPA symbols. Listeners responded by selecting the AE category containing the vowel most similar to the one in the utterance and rating its ‘‘goodness of fit.’’ The percentages of selection of the modal AE response category for each NG vowel ranged from 99% for /i/→/i/ (best fit) to 41% for /o//→/u/ (worst fit). NG front and back rounded vowels were assimilated to AE back rounded vowels. However, for seven vowels, modal category percentages differed by greater than 15% across the five consonantal contexts. There was also significant variation in assimilation patterns across the four speaker groups for 11 of the NG vowels. These results have implications for theories of L2 speech learning. [Work supported by NIDCD.]
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