Vowel Enhancement in Early Stage Spanish Esophageal Speech Using Natural Glottal Flow Pulse and Vocal Tract Frequency Warping Rizwan Ishaq author Dhanananjaya Gowda author Paavo Alku author Begonya Garcia Zapirain author 2015-09 text Proceedings of SLPAT 2015: 6th Workshop on Speech and Language Processing for Assistive Technologies Jan Alexandersson editor Ercan Altinsoy editor Heidi Christensen editor Peter Ljunglöf editor François Portet editor Frank Rudzicz editor Association for Computational Linguistics Dresden, Germany conference publication ishaq-etal-2015-vowel 10.18653/v1/W15-5110 https://aclanthology.org/W15-5110/ 2015-09 55 59