Google-Read-Aloud is the user agent for the Google Read Aloud service. This service enables reading web pages using text-to-speech (TTS). This service is activated when an end user has text to speech enabled and visits a page. The Read Aloud service is used by Google Go.
Crawl frequency and behavior
Google Read Aloud is triggered by a user request. Google Read Aloud conserves bandwidth by caching page results, so you should not see more than one request every few hours for a given page.
Google Read Aloud is not a web crawler: Google Read Aloud fetches only one page at a time, according to a user read request, and it doesn't follow hyperlinks. A user request for listening to a web page results in either zero or one visit to a page, depending on whether the page has been fetched recently.
Google Read Aloud ignores robots.txt rules
Google Read Aloud acts as a direct agent of a human user, not as a robot, so it ignores robots.txt rules.
What is the google-speakr agent?
The google-speakr agent is an older version of the user agent that is now deprecated. Its new name is Google-Read-Aloud.