Why is the 'er' missing in the pronunciation? Ve ge ta ri an er en
In some dialects in Norway they use something called a "retrofleks" (a sound pronounced by bending the tip of the tongue upwards and backwards against the roof of the mouth). The eastern parts of Norway often has those.
Some groups of consonants is being pronounced together (and the result is the missing "er" in e.g. vegetarianeren---->vegetarianer'n).
In dialects without the retrofleks, all the sounds are pronounced.
(I'm not 100% sure about the details here as I never use these sounds myself)