The Pronunciation of the TU Combination in The Common Tongue of the English Language, when it is located in the middle of the word (or at least not at the beginning of the word.)
As you can see — whenever the letter “u” follows the letter “t” in a word, it causes the letter “t” to be pronounced as the “ch” combination. The letter “u” is still pronounced as a separate letter though and is usually either pronounced “long” (as in the word, “Actual”) or can disappear (as in the word, “Adventure”, and almost every other word with the “-ture” suffix.)
However, as you will see in the video below, this is not the case when the TU combination happens at the beginning of a word, such as: “Tunnel“
Pretty simple, right? Well, that is the way it should be. Let me know if there is any other bit of pronunciation that I can help you with. Of course, you can go to YouTube and look up videos on your own… However — just because a video is on YouTube, does not mean that it is actually “good”… (This one is though) 😎
Have An Excellent Day!