|Review Comment: |
The paper extends the authors' earlier work on using
controlled natural language (CNL) in semantic OWL-based wikis.
The novelty in this paper is to investigate this in the multi-lingual
case. CNL statements, transformed into OWL, can here not only be given
in different languages (here in particular in Englishm German, and Spanish)
but also translated arcross language boundaries facilitating using wiki
CNL in different languages. The paper expands the authors' recent ESWC 2013
The topic is clearly suitable for the topic of the special issue.
The research problem and methods used for attacking it are clearly stated.
Related work is discussed in a separate section, which seems adequate, although
I am not an expert in this particular field.
The papers cover a great deal of work related to the underlying tools and new
experiments, with illustrative examples and pointers to further sources.
After presenting the framework, the quality of the translations arcross natural
languages is evaluated and results analysed in careful way.
The language and presentation is exceptionally well polished.
In short, this looks like solid work worth publishing.
My main concern about the paper is related to the general idea of using CNL as a basis in wikis in general. What would be the *realistic* use case problem for a system like this, and how well would it then actually solve the problem of collaboarative multilingual ontology creation? The paper concerns a toy example of countries, rivers etc. It is good to use such examples in a research setting, but it would be nice if the authors could shortly discuss this bigger question and e.g. motive the reader by examples of more serious CNL-based wikis and OWL ontologies - are there useful systems already and what are the challenges? It is a challenge, if a group of people start inputting CNL OWL expressions in a wiki, and this should coverge into something logically consistent and useful. Some challenges encountered in the evaluation section are discussed, e.g., different opinions people may have about geography, which leads to inconsistency. It is also said in the paper that 80% of the users could not express themselves as they liked in the experiment. In footnote 9 the authors point the reader to "demo wikis", but I could not find any realistic applications or datasets there. The video there was for some reason not operational.
p. 2 Provide the reference to GF when it is first mentioned.
Use mdash "---" without spaces at its ends. There are many occurrences of this.
"as already mentioned" -- Remove, it is not good style to use expressions like this.
" discusses a multilingual ..." Using a reference as a word does not look nice. E.g. "Davis et al.  discuss ..." would be better. There are many occurrences of this.
In Fig. 6 the "proper name" column contains adjectives "Spanish" and "Swedish". Explain or correct this.
 Journal name "Semantic Web" is not complete.
 Pages missing.