How the word "thirty" is translated into English
The bus comes every thirty minutes.
[ðə ˈbəs ˈkəmz ˈɛvri ˈθɜrti ˈmɪnəts.]
There are thirty students in my class.
[ˈðɛr ˈɑr ˈθɜrti ˈstudn̩ts ˈɪn ˈmaɪ ˈklæs.]
I'm not thirty yet!
[ˈaɪm ˈnɑt ˈθɜrti ˈjɛt!]
"thirty" is in the lesson "Big numbers" (Level 4), along with 11 other useful words. LinDuo has 180 topic lessons like this one, 2,375 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.