My mic on duolingo wont work i need help!
If this is via the browser, try using the Chrome browser as that supports the new voice API which duolingo are now using.
Adding on to Psionpete's excellent answer, here's a blurb from the "Help" section of Duolingo:
Why don't I get speaking exercises anymore?
Speaking exercises on the new website only work on browsers that support the Web Speech API, the most popular being Chrome. Unfortunately, the old speech system was outdated and a burden on our system. If you use the Chrome browser, you will get speaking exercises again.
tick the lock symbol(above the page) . find microphone and choose the permission