The two speakers in the Arabic course pronounce words completely differently . One will make a word two syllables long , and the other one . Vowels can be long or short . A r turns into a l. A final l vanishes . I understand that there are different dialects , but two such utterly dissimilar ones in the same lesson ? It’s like learning two different languages
The Duolingo course teaches MSA, so there should be no difference and no dialects at all. As each letter has a distinct pronunciation, shortening or prolonging makes no difference as it is the same one sound. Actually the shortening/prolonging is sometimes a form of art and fluency which is practiced a lot by Quran readers and musicians, just like in American music "I love youuuuuuuuuu u u u" :P
An R never turns into an L, nor does a final L vanish.