Why is the tanwiin pronounced at the end of this sentence?
I have just started learning Arabic online, and one of the lessons said that a tanwiin is never pronounced if it falls at the end of the sentence. However, then the website presented this sentence (I apologize; it did not allow me to copy and paste the actual Arabic characters):
al-ma'kuulaatu-l-3arabiyyatu tu3jibunii jiddan
Why is the tanwiin still pronounced in "jiddan," since it falls at the end of the sentence?
Thank you in advance for your help!