I wrote a prototype that analyzes natural language in English and German with https://spacy.io/ and translates it into SPARQL queries to Wikidata. It's incredibly primitive, but looks promising so far.
$ python3 nlqa.py --question="Was ist die Hauptstadt von Angola?" --language=de
$ python3 nlqa.py --question="What is Estonia's national currency?" --language=en
Generalistic and moderated instance. All opinions are welcome, but hate speeches are prohibited. Users who don't respect rules will be silenced or suspended, depending on the violation severity.