If you're looking for a tool that combines text-to-speech with Google Classroom, Kurzweil Education is a great option. The tool is part of a suite of assistive technology designed to help students with learning difficulties. It's got text-to-speech support in 13 languages and 18 dialects and speech-to-text support for dictation and note-taking. It integrates with Google Classroom and other learning management systems, and it's a good option for students with dyslexia, visual impairments and English language learners.
Another good option is NaturalReader, a full-featured text-to-speech tool that can handle PDF and Word documents. It's got natural-sounding voices in more than 50 languages and assistive technology tools for people with dyslexia, ADHD and other learning difficulties. NaturalReader also has a web app, mobile app and Chrome extension, so you can use it for personal and educational purposes.
If you want something more interactive, check out Kami. The tool has a variety of annotation and assessment tools, including Read Aloud and Voice and Video Comments. Kami integrates with Google Classroom and other popular learning tools, giving teachers a lot of tools to get students more engaged and to track student progress. The premium Teacher Plan gives you access to all 40+ tools and features, and the School or District Plan offers custom support and domain-wide deployment.