Added icons for flags, improvements in voice mixer

README.md

@@ -163,7 +163,7 @@ Feel free to explore the code and make any changes you like.
 - Abogen uses [Kokoro](https://github.com/hexgrad/kokoro) for its high-quality, natural-sounding text-to-speech synthesis. Huge thanks to the Kokoro team for making this possible.
 - Thanks to [@wojiushixiaobai](https://github.com/wojiushixiaobai) for [Embedded Python](https://github.com/wojiushixiaobai/Python-Embed-Win64) packages. These modified packages include pip pre-installed, enabling Abogen to function as a standalone application without requiring users to separately install Python in Windows.
 - Special thanks to the [PyQt](https://www.riverbankcomputing.com/software/pyqt/) team for providing the cross-platform GUI toolkit that powers Abogen's interface.
-- [Female](https://icons8.com/icon/uI49hxbpxTkp/female), [Male](https://icons8.com/icon/12351/male) and [Mix](https://icons8.com/icon/21700/adjust) icons by [Icons8](https://icons8.com/).
+- [US](https://icons8.com/icon/aRiu1GGi6Aoe/usa), [Great Britain](https://icons8.com/icon/t3NE3BsOAQwq/great-britain), [Spain](https://icons8.com/icon/ly7tzANRt33n/spain), [France](https://icons8.com/icon/3muzEmi4dpD5/france), [India](https://icons8.com/icon/esGVrxg9VCJ1/india), [Italy](https://icons8.com/icon/PW8KZnP7qXzO/italy), [Japan](https://icons8.com/icon/McQbrq9qaQye/japan), [Brazil](https://icons8.com/icon/zHmH8HpOmM90/brazil), [China](https://icons8.com/icon/Ej50Oe3crXwF/china), [Female](https://icons8.com/icon/uI49hxbpxTkp/female), [Male](https://icons8.com/icon/12351/male) and [Mix](https://icons8.com/icon/21700/adjust) icons by [Icons8](https://icons8.com/).
 
 ## `License`
 This project is available under the MIT License - see the [LICENSE](https://github.com/denizsafak/abogen/blob/main/LICENSE) file for details.