Learn Farsi: دهانم بسته است.

In Farsi, instead of using a separate word for my, you can add the ending -am directly to the noun. Here, dahan means mouth, so adding -am makes dahanam, meaning my mouth. This attached ending is called a possessive enclitic.

Could I say dahan-e man instead of dahanam?

Yes! dahan-e man (using the separate pronoun for my) and dahanam (using the attached ending) mean exactly the same thing. The attached ending -am is simply a shorter, very natural option that Farsi speakers use constantly.

How does the ending -am attach to dahan in pronunciation?

Because the word dahan (mouth) ends in a consonant sound (n), the -am attaches smoothly to make dahan-am. You don't need to add any extra linking letters, which you sometimes need when attaching these endings to a noun that ends in a vowel.

Why is the word ast at the very end of the sentence?

Farsi typically puts the verb at the very end of the sentence. Since ast means is, it acts as the main verb, so it naturally comes after the adjective baste (closed).