I got this question on my Drift chatbot.
Yes, you can use any language for your webhook, and Python is a good choice considering that many beginners find it quite easy to learn.
Generally speaking, you should choose the language you are most comfortable with.
However, if you are building a Google Assistant app, I recommend using NodeJS because the documentation is much better for Node when compared to the other languages.
Don't forget to watch my mini-course which helps you understand the request-response cycle of a webhook. Learning this concept well will make it much easier for you to build your bot.
Also, check out my Dialogflow Webhooks course which will help you get started. 🙂 The code samples are in PHP, but the PHP code is very simple to read and you will probably won't find it difficult to port it to other languages.