Step 1: Understand the task
The task is to find a free AI voice generator or tool that can provide texttospeech functionality.

Step 2: Research available options
There are several online platforms and tools that offer free AI voice generation、Some popular ones include Google TexttoSpeech, Amazon Polly, and Microsoft Azure Cognitive Services Speech Services、However, not all of them are entirely free.

Step 3: List potential free AI voice generators
1、Google TexttoSpeech: Offers a range of voices and languages、It's available through the Google Cloud TexttoSpeech API, which has a free tier.
2、Balabolka: A free texttospeech software that supports multiple voices and can read text from various formats.
3、NaturalReader: Offers a free version with limited features and voices、It's userfriendly and supports multiple file formats.
4、TTSMP3: A simple online tool that converts text to speech for free, supporting several voices and languages.
5、OnlineTTS: Another online tool that offers texttospeech conversion for free, with various voice options.

Step 4: Evaluate the options
Google TexttoSpeech and Microsoft Azure Cognitive Services Speech Services are powerful but might require more technical setup and have usage limits on their free tiers.
Balabolka and NaturalReader are software solutions that can be downloaded and used offline after initial download.
TTSMP3 and OnlineTTS are straightforward online tools that don't require any software installation.

Step 5: Conclusion
For a free AI voice generator, one can consider the options listed above based on their specific needs, such as the need for offline capability, ease of use, or the range of voices and languages supported.

The final answer is:
Some popular free AI voice generators include Google TexttoSpeech, Balabolka, NaturalReader, TTSMP3, and OnlineTTS.