When a user utilizes the text-to-speech feature for a lesson (by clicking the 'Start Listening' button to listen to the entire lesson), an additional 50 seconds is added to their total time usage for that lesson. This additional time is counted only once per lesson during a single session, even if the text-to-speech feature is used multiple times, as long as the page is not refreshed. Note: Listening to selected text is free and does not count towards the total time usage.