Why is もっと pronounced "motto" but written "motsuto"? Word **** is pronuncing as **motto** means more. But when writing It is **mo() tsu() to()**. Why is that ? I'm new to Japanese language. Please tell me there are other commonly used words like this ? Please give me some examples.

This is a double consonant sound. It's denoted by the smaller size ****. So instead of the word being pronounced as **Mo-tsu-to** , it is pronounced **Mot-to** because of the ****. That is why you have two _t_ 's instead of just Mo-to. This is similar to **** in which the actual pronunciation is **kat-ta** instead of **ka-tsu-ta.** Another consonant sound is added before **** that is similar to the one following it. That is why in both **** and **** the tsu is replaced by a "t" because the kana following **** are **** and **** , which both start with a "t" sound. This is why it is called a double consonant sound.