Because this is what the phrase means in German. In English, "The restaurant is left" doesn't make sense. Word-for-word translation between German and English rarely works as intended.
Agreed. I didn't want to put "the restaurant is left", but it was given as the correct answer when I tried "the restaurant is left of here". "on the left" is probably the closest translation
Saying "The restaurant is left" would make a native speaker think first, "The restaurant is remaining". Think if a fire happened on a city block, but a restaurant survived. You could then say, "The restaurant is left". If you wanted to give directions or imply location, you have to use a preposition like "on the" or "to the".
Think of it as "leftish" or "leftly" if you want a word-for-word translation. Regardless, as SamirShaker noted, links means "has the quality of being on, to, or for the left" and doesn't necessarily require the prepositions.
Is 'das Restaurant' pronounced with a French accent? (nasal pronunciation /restawrã/)
Yes. A lot of words borrowed from French keep their French pronunciation, although the spelling may change sometimes. For example: das Menü, das Büro, der Chef, die Chance, das Café, etc...
Here is a more complete list of German words borrowed from French if you're interested: http://german.about.com/library/blvoc_french01.htm
Well a German guy told me that they also use "trottoir" (pedestrian road), which is not given on your website :-) But thank you all the same !
That works sometimes if there is something (like a street) that splits left from right. Then there is a left side and a right side. Sometimes you could be giving directions where there is not on obvious split and you are at the point at which you want them to look left, because that is where it will be.