In conclusion, Ivona and Eric are two significant TTS systems that have shaped the TTS landscape. Ivona's pioneering work in concatenative TTS and Eric's advanced deep learning-based approach have pushed the boundaries of what is possible with TTS technology. As TTS technology continues to evolve, we can expect even more natural-sounding speech and innovative applications. The impact of Ivona and Eric will be felt for years to come, as they have paved the way for a new generation of TTS systems that are transforming the way we interact with machines.