My current research topics:

• Neural model of speech production, perception, and acquisition
• Articulatory-acoustic synthesis of speech and singing
• Treatment of speech disorders using SpeechTrainer
• Acoustic and perceptual methods in diagnosis of speech disorders

• Dipl.-Inf. Jim Kannampuzha (wiss. Mitarbeiter)
  
• Cornelia Eckers, M.Sc. (wiss. Mitarbeiterin)
  

Neural model of speech production, perception, and acquisition (theoretical neuroscience, systemic neuroscience)
See also: Wikipedia: Neurocomputaional Speech Processing
A neural model for sensorimotor control of speech is developed on the basis of a three-dimensional articulatory-acoustic model.

• Neurocomputational model of speech processing:
  see pdfs of an introductory lecture: part 1: production and acquisition, part 2: perception and the concept of actions
  Papers on this topic started in 2006 (see publications)
• 3D-articulatory-acoustic model:
  The 3D-model is developed by Peter Birkholz, Aachen.
  

Articulatory-acoustic synthesis of speech and singing
An 3D-articulatory-acoustic synthesizer including a gestural control concept has been developed for high quality synthesis of speech and singing.
Currently the model is capable of synthesizing unrestricted text including all sound types (vowels, plosives, fricatives, ...) and unrestricted songs for untrained male and female voices. (Birkholz & Kröger 2007: Abstracts of PEVOC, Groningen, Posters). In the case of singing it is planned to implement professional singing voices (e.g. a baritone voice).

Examples:
Video and sound example for speech: Naechster Halt Hamburg
Sound example for singing: Dona Nobis Pacem

Synthesis of Singing Challenge (during INTERSPEECH 2007, Antwerp): Contest of 6 singing synthesis systems: 2nd place for the Birkholz 3D-articulatory-acoustic model

Overview: research topics

Treatment of speech disorders using SpeechTrainer
SpeechTrainer is a software-package for 2D-visualisation of speech movements (download SpeTra). SpeechTrainer can be used as a visual stimulation technique in treatment of different types of speech disorders. (see Funk_2006, Kröger_2005 )

• Use of SpeTra in treatment of articulation disorders:
  Albert_diploma_thesis_2005
• Use of SpeTra in treatment of apraxia of speech:
  Gotto_diploma_thesis_2005

• Funk J, Montanus S, Kröger BJ (2006) Therapie von neurogenen und kindlichen Sprechstörungen mit dem Programm SpeechTrainer. Forum Logopädie 20 (2): 6-13 (pdf)
• Kröger BJ, Gotto J, Albert S, Neuschaefer-Rube C (2005) A visual articulatory model and ist application to therapy of speech disorders: a pilot study. In: S Fuchs, P Perrier, B Pompino-Marschall (Hrsg.) Speech production and perception: Experimental analyses and models. ZASPiL 40: 79-94. (pdf)

Acoustic and perceptual methods in diagnosis of speech disorders
Phonetically oriented methods in diagnosis of speech disorders are mainly perceptually based. The main drawback of these methods is its subjectivity. Thus acoustically based methods could be advantageous. But the main problem of acoustically based methods in diagnosis of speech disorders is to extract meaningful or significant acoustic parameters.
Different phonetically oriented measures were tested for improving or refining the diagnosis of speech disorders.

• Childhood apraxia of speech:
  
  • Franz_ICSMC_2006


• Dysarthria:
  
  • Kröger_DAGA_2005
  • Kröger_DAGA_2003
  • Siegert_diploma_thesis_2004

• Franz, E, Willmes K, Neuschaefer-Rube C, Kröger BJ (2006) Acoustical and perceptive analyses of vowels in suspected developmental apraxia of speech: a pilot study. Abstracts of 5th International Conference of Speech Motor Control (Nijmegen, Netherlands). Also: Stem-, Spraak- en Taalpathologie 14, Suppl. p. 89. (pdf)
• Kröger BJ, Diem A, Siegert M (2003) Artikulatorische und akustische Methoden in der Diagnostik und Therapie von Sprechstörungen. In: Fortschritte der Akustik: 29. Deutsche Jahrestagung für Akustik, DAGA '03. DEGA, Oldenburg, pp. 754-755. (pdf)
• Kröger BJ, Siegert M, Neuschaefer-Rube C (2005) Phonatorisch-artikulatorische Kompensation bei einem ALS-Patienten mit schwerer dysarthrischer Sprechstörung. In: Fortschritte der Akustik: 31. Deutsche Jahrestagung für Akustik, DAGA '05. DEGA, Berlin, pp. 75-76. (pdf)